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Everything has now been moved to a separate repository at
https://github.com/GrammaticalFramework/gf-contrib
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-abstract Elements = Merge ** {

-

-  --  Silvery radioactive metallic element, belongs to 

-  -- group 3 of the periodic table. The most stable isotope, Ac_227, has a 

-  -- half_life of 217 years. Ac_228 (half_life of 6.13 hours) also occurs in 

-  -- nature. There are 22 other artificial isotopes, all radioactive and 

-  -- having very short half_lives. Chemistry similar to lanthanum. Used as a 

-  -- source of alpha particles. Discovered by A. Debierne in 1899.

-  fun Actinium : Class ;

-  fun Actinium_Class : SubClass Actinium ElementalSubstance ;

-

-  -- Silvery_white lustrous metallic element of group 

-  -- 3 of the periodic table. Highly reactive but protected by a thin 

-  -- transparent layer of the oxide which quickly forms in air. There are many 

-  -- alloys of aluminum, as well as a good number of industrial uses. Makes up 

-  -- 8.1 percent of the Earth's crust, by weight. Isolated in 1825 by H.C. 

-  -- Oersted.

-  fun Aluminum : Class ;

-  fun Aluminum_Class : SubClass Aluminum ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element, 

-  -- belongs to the actinoids. Ten known isotopes. Am_243 is the most stable 

-  -- isotope, with a half_life of 7.95*10^3 years. Discovered by Glenn T. 

-  -- Seaborg and associates in 1945, it was obtained by bombarding 

-  -- {uranium}_238 with alpha particles.

-  fun Americium : Class ;

-  fun Americium_Class : SubClass Americium ElementalSubstance ;

-

-  -- Element of group 15. Multiple allotropic forms. 

-  -- The stable form of antimony is a blue_white metal. Yellow and black 

-  -- antimony are unstable non_metals. Used in flame_proofing, paints, 

-  -- ceramics, enamels, and rubber. Attacked by oxidizing acids and halogens. 

-  -- First reported by Tholden in 1450.

-  fun Antimony : Class ;

-  fun Antimony_Class : SubClass Antimony ElementalSubstance ;

-

-  -- Monatomic noble gas. Makes up 0.93 percent of the 

-  -- air. Colourless, odorless. Is inert and has no true compounds. Lord 

-  -- Rayleigh and Sir william Ramsey identified argon in 1894.

-  fun Argon : Class ;

-  fun Argon_Class : SubClass Argon ElementalSubstance ;

-

-  -- Metalloid element of group 15. There are three 

-  -- allotropes, yellow, black, and grey. Reacts with halogens, concentrated 

-  -- oxidizing acids and hot alkalis. Albertus Magnus is believed to have been 

-  -- the first to isolate the element in 1250.

-  fun Arsenic : Class ;

-  fun Arsenic_Class : SubClass Arsenic ElementalSubstance ;

-

-  -- Radioactive halogen element. Occurs naturally 

-  -- from uranium and thorium decay. At least 20 known isotopes. At_210, the 

-  -- most stable, has a half_life of 8.3 hours. Synthesized by nuclear 

-  -- bombardment in 1940 by D.R. Corson, K.R. MacKenzie and E. Segre at the 

-  -- University of California.

-  fun Astatine : Class ;

-  fun Astatine_Class : SubClass Astatine ElementalSubstance ;

-

-  -- Silvery_white reactive element, belonging to group 

-  -- 2 of the periodic table. Soluble barium compounds are extremely 

-  -- poisonous. Identified in 1774 by Karl Scheele and extracted in 1808 by 

-  -- Humphry Davy.

-  fun Barium : Class ;

-  fun Barium_Class : SubClass Barium ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element. 

-  -- Belongs to actinoid series. Eight known isotopes, the most common Bk_247, 

-  -- has a half_life of 1.4*10^3 years. First produced by Glenn T. Seaborg 

-  -- and associates in 1949 by bombarding americium_241 with alpha 

-  -- particles.

-  fun Berkelium : Class ;

-  fun Berkelium_Class : SubClass Berkelium ElementalSubstance ;

-

-  -- Grey metallic element of group 2 of the periodic 

-  -- table. Is toxic and can cause severe lung diseases and dermatitis. Shows 

-  -- high covalent character. It was isolated independently by F. Wohler and 

-  -- A.A. Bussy in 1828.

-  fun Beryllium : Class ;

-  fun Beryllium_Class : SubClass Beryllium ElementalSubstance ;

-

-  -- White crystalline metal with a pink tinge, belongs 

-  -- to group 15. Most diamagnetic of all metals and has the lowest thermal 

-  -- conductivity of all the elements except mercury. Lead_free bismuth 

-  -- compounds are used in cosmetics and medical procedures. Burns in the air 

-  -- and produces a blue flame. In 1753, C.G. Junine first demonstrated that 

-  -- it was different from lead.

-  fun Bismuth : Class ;

-  fun Bismuth_Class : SubClass Bismuth ElementalSubstance ;

-

-  -- An element of group 13 of the periodic table. There 

-  -- are two allotropes, amorphous boron is a brown power, but metallic boron 

-  -- is black. The metallic form is hard (9.3 on Mohs' scale) and a bad 

-  -- conductor in room temperatures. It is never found free in nature. 

-  -- Boron_10 is used in nuclear reactor control rods and shields. It was 

-  -- discovered in 1808 by Sir Humphry Davy and by J.L. Gay_Lussac and L.J. 

-  -- Thenard.

-  fun Boron : Class ;

-  fun Boron_Class : SubClass Boron ElementalSubstance ;

-

-  -- Halogen element. Red volatile liquid at room 

-  -- temperature. Its reactivity is somewhere between chlorine and iodine. 

-  -- Harmful to human tissue in a liquid state, the vapour irritates eyes and 

-  -- throat. Discovered in 1826 by Antoine Balard.

-  fun Bromine : Class ;

-  fun Bromine_Class : SubClass Bromine ElementalSubstance ;

-

-  -- Soft bluish metal belonging to group 12 of the 

-  -- periodic table. Extremely toxic even in low concentrations. Chemically 

-  -- similar to zinc, but lends itself to more complex compounds. Discovered 

-  -- in 1817 by F. Stromeyer.

-  fun Cadmium : Class ;

-  fun Cadmium_Class : SubClass Cadmium ElementalSubstance ;

-

-  -- Soft silvery_white metallic element belonging to 

-  -- group 1 of the periodic table. One of the three metals which are liquid 

-  -- at room temperature. Cs_133 is the natural, and only stable, isotope. 

-  -- Fifteen other radioisotopes exist. Caesium reacts explosively with cold 

-  -- water, and ice at temperatures above 157K. Caesium hydroxide is the 

-  -- strongest base known. Caesium is the most electropositive, most alkaline 

-  -- and has the least ionization potential of all the elements. Known uses 

-  -- include the basis of atomic clocks, catalyst for the hydrogenation of some 

-  -- organic compounds, and in photoelectric cells. Caesium was discovered by 

-  -- Gustav Kirchoff and Robert Bunsen in Germany in 1860 spectroscopically. 

-  -- Its identification was based upon the bright blue lines in its spectrum. 

-  -- The name comes from the latin word caesius, which means sky blue. Caesium 

-  -- should be considered highly toxic. Some of the radioisotopes are even 

-  -- more toxic.

-  fun Caesium : Class ;

-  fun Caesium_Class : SubClass Caesium ElementalSubstance ;

-

-  -- Soft grey metallic element belonging to group 2 of 

-  -- the periodic table. Used a reducing agent in the extraction of thorium, 

-  -- zirconium and uranium. Essential element for living organisms.

-  fun Calcium : Class ;

-  fun Calcium_Class : SubClass Calcium ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element. 

-  -- Belongs to actinoid series. Cf_251 has a half life of about 700 years. 

-  -- Nine isotopes are known. Cf_252 is an intense {neutron} source, which 

-  -- makes it an intense {neutron} source and gives it a use in {neutron} 

-  -- activation analysis and a possible use as a radiation source in medicine. 

-  -- First produced by Glenn T. Seaborg and associates in 1950.

-  fun Californium : Class ;

-  fun Californium_Class : SubClass Californium ElementalSubstance ;

-

-  -- Carbon is a member of group 14 of the periodic 

-  -- table. It has three allotropic forms of it, diamonds, graphite and 

-  -- fullerite. Carbon_14 is commonly used in radioactive dating. Carbon 

-  -- occurs in all organic life and is the basis of organic chemistry. Carbon 

-  -- has the interesting chemical property of being able to bond with itself, 

-  -- and a wide variety of other elements.

-  fun Carbon : Class ;

-  fun Carbon_Class : SubClass Carbon ElementalSubstance ;

-

-  -- Silvery metallic element, belongs to the 

-  -- lanthanoids. Four natural isotopes exist, and fifteen radioactive 

-  -- isotopes have been identified. Used in some rare_earth alloys. The 

-  -- oxidized form is used in the glass industry. Discovered by Martin .H. 

-  -- Klaproth in 1803.

-  fun Cerium : Class ;

-  fun Cerium_Class : SubClass Cerium ElementalSubstance ;

-

-  -- Halogen element. Poisonous greenish_yellow gas. 

-  -- Occurs widely in nature as sodium chloride in seawater. Reacts directly 

-  -- with many elements and compounds, strong oxidizing agent. Discovered by 

-  -- Karl Scheele in 1774. Humphrey David confirmed it as an element in 

-  -- 1810.

-  fun Chlorine : Class ;

-  fun Chlorine_Class : SubClass Chlorine ElementalSubstance ;

-

-  -- Hard silvery transition element. Used in 

-  -- decorative electroplating. Discovered in 1797 by Vauquelin.

-  fun Chromium : Class ;

-  fun Chromium_Class : SubClass Chromium ElementalSubstance ;

-

-  -- Light grey transition element. Some meteorites 

-  -- contain small amounts of metallic cobalt. Generally alloyed for use. 

-  -- Mammals require small amounts of cobalt salts. Cobalt_60, an artificially 

-  -- produced radioactive isotope of Cobalt is an important radioactive tracer 

-  -- and cancer_treatment agent. Discovered by G. Brandt in 1737.

-  fun Cobalt : Class ;

-  fun Cobalt_Class : SubClass Cobalt ElementalSubstance ;

-

-  -- Red_brown transition element. Known by the Romans 

-  -- as 'cuprum.' Extracted and used for thousands of years. Malleable, 

-  -- ductile and an excellent conductor of heat and electricity. When in moist 

-  -- conditions, a greenish layer forms on the outside.

-  fun Copper : Class ;

-  fun Copper_Class : SubClass Copper ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element. Belongs 

-  -- to actinoid series. Nine known isotopes, Cm_247 has a half_life of 

-  -- 1.64*10^7 years. First identified by Glenn T. Seaborg and associates in 

-  -- 1944, first produced by L.B. Werner and I. Perlman in 1947 by bombarding 

-  -- americium_241 with {neutron}s. Named for Marie Curie.

-  fun Curium : Class ;

-  fun Curium_Class : SubClass Curium ElementalSubstance ;

-

-  -- Metallic with a bright silvery_white lustre. 

-  -- Dysprosium belongs to the lanthanoids. It is relatively stable in air at 

-  -- room temperatures, it will however dissolve in mineral acids, evolving 

-  -- hydrogen. It is found in from rare_earth minerals. There are seven 

-  -- natural isotopes of dysprosium, and eight radioisotopes, Dy_154 being the 

-  -- most stable with a half_life of 3*10^6 years. Dysprosium is used as a 

-  -- neutron absorber in nuclear fission reactions, and in compact disks. It 

-  -- was discovered by Paul Emile Lecoq de Boisbaudran in 1886 in France. Its 

-  -- name comes from the Greek word dysprositos, which means hard to obtain.

-  fun Dysprosium : Class ;

-  fun Dysprosium_Class : SubClass Dysprosium ElementalSubstance ;

-

-  -- Appearance is unknown, however it is most 

-  -- probably metallic and silver or gray in color. Radioactive metallic 

-  -- transuranic element belonging to the actinoids. Es_254 has the longest 

-  -- half_life of the eleven known isotopes at 270 days. First identified by 

-  -- Albert Ghiorso and associates in the debris of the 1952 hydrogen bomb 

-  -- explosion. In 1961 the first microgram quantities of Es_232 were 

-  -- separated. While einsteinium never exists naturally, if a sufficient 

-  -- amount was assembled, it would pose a radiation hazard.

-  fun Einsteinium : Class ;

-  fun Einsteinium_Class : SubClass Einsteinium ElementalSubstance ;

-

-  -- Soft silvery metallic element which belongs to the 

-  -- lanthanoids. Six natural isotopes that are stable. Twelve artificial 

-  -- isotopes are known. Used in nuclear technology as a neutron absorber. It 

-  -- is being investigated for other possible uses. Discovered by Carl G. 

-  -- Mosander in 1843.

-  fun Erbium : Class ;

-  fun Erbium_Class : SubClass Erbium ElementalSubstance ;

-

-  -- Soft silvery metallic element belonging to the 

-  -- lanthanoids. Eu_151 and Eu_153 are the only two stable isotopes, both of 

-  -- which are {neutron} absorbers. Discovered in 1889 by Sir William 

-  -- Crookes.

-  fun Europium : Class ;

-  fun Europium_Class : SubClass Europium ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element, belongs 

-  -- to the actinoids. Ten known isotopes, most stable is Fm_257 with a 

-  -- half_life of 10 days. First identified by Albert Ghiorso and associates 

-  -- in the debris of the first hydrogen_bomb explosion in 1952.

-  fun Fermium : Class ;

-  fun Fermium_Class : SubClass Fermium ElementalSubstance ;

-

-  -- A poisonous pale yellow gaseous element belonging 

-  -- to group 17 of the periodic table (The halogens). It is the most 

-  -- chemically reactive and electronegative element. It is highly dangerous, 

-  -- causing severe chemical burns on contact with flesh. Fluorine was 

-  -- identified by Scheele in 1771 and first isolated by Moissan in 1886.

-  fun Fluorine : Class ;

-  fun Fluorine_Class : SubClass Fluorine ElementalSubstance ;

-

-  -- Radioactive element, belongs to group 1 of the 

-  -- periodic table. Found in uranium and thorium ores. The 22 known isotopes 

-  -- are all radioactive, with the most stable being Fr_223. Its existence was 

-  -- confirmed in 1939 by Marguerite Perey.

-  fun Francium : Class ;

-  fun Francium_Class : SubClass Francium ElementalSubstance ;

-

-  -- Soft silvery metallic element belonging to the 

-  -- lanthanoids. Seven natural, stable isotopes are known in addition to 

-  -- eleven artificial isotopes. Gd_155 and Gd_157 and the best neutron 

-  -- absorbers of all elements. Gadolinium compounds are used in electronics. 

-  -- Discovered by J.C.G Marignac in 1880.

-  fun Gadolinium : Class ;

-  fun Gadolinium_Class : SubClass Gadolinium ElementalSubstance ;

-

-  -- Soft silvery metallic element, belongs to group 13 

-  -- of the periodic table. The two stable isotopes are Ga_69 and Ga_71. 

-  -- Eight radioactive isotopes are known, all having short half_lives. 

-  -- Gallium Arsenide is used as a semiconductor. Corrodes most other metals 

-  -- by diffusing into their lattice. First identified by Francois Lecoq de 

-  -- Boisbaudran in 1875.

-  fun Gallium : Class ;

-  fun Gallium_Class : SubClass Gallium ElementalSubstance ;

-

-  -- Lustrous hard metalloid element, belongs to 

-  -- group 14 of the periodic table. Forms a large number of organometallic 

-  -- compounds. Predicted by Mendeleev in 1871, it was actually found in 1886 

-  -- by Winkler.

-  fun Germanium : Class ;

-  fun Germanium_Class : SubClass Germanium ElementalSubstance ;

-

-  -- Gold is gold colored. It is the most malleable and 

-  -- ductile metal known. There is only one stable isotope of gold, and five 

-  -- radioisotopes of gold, Au_195 being the most stable with a half_life of 

-  -- 186 days. Gold is used as a monetary standard, in jewelry, dentistry, 

-  -- electronics. Au_198 is used in treating cancer and some other medical 

-  -- conditions. Gold has been known to exist as far back as 2600 BC. Gold 

-  -- comes from the Anglo_Saxon word gold. Its symbol, Au, comes from the 

-  -- Latin word aurum, which means gold. Gold is not particularly toxic, 

-  -- however it is known to cause damage to the liver and kidneys in some.

-  fun Gold : Class ;

-  fun Gold_Class : SubClass Gold ElementalSubstance ;

-

-  -- Silvery lustrous metallic transition element. 

-  -- Used in tungsten alloys in filaments and electrodes, also acts as a 

-  -- neutron absorber. First reported by Urbain in 1911, existence was finally 

-  -- established in 1923 by D. Coster, G.C. de Hevesy in 1923.

-  fun Hafnium : Class ;

-  fun Hafnium_Class : SubClass Hafnium ElementalSubstance ;

-

-  -- Colourless, odourless gaseous nonmetallic element. 

-  -- Belongs to group 18 of the periodic table. Lowest boiling point of all 

-  -- elements and can only be solidified under pressure. Chemically inert, no 

-  -- known compounds. Discovered in the solar spectrum in 1868 by Lockyer.

-  fun Helium : Class ;

-  fun Helium_Class : SubClass Helium ElementalSubstance ;

-

-  -- Relatively soft and malleable silvery_white 

-  -- metallic element, which is stable in dry air at room temperature. It 

-  -- oxidizes in moist air and at high temperatures. It belongs to the 

-  -- lanthanoids. A rare_earth metal, it is found in the minerals monazite and 

-  -- gadolinite. It possesses unusual magnetic properties. One natural 

-  -- isotope, Ho_165 exists, six radioisotopes exist, the most stable being 

-  -- Ho_163 with a half_life of 4570 years. Holmium is used in some metal 

-  -- alloys, it is also said to stimulate the metabolism. Discovered by Per 

-  -- Theodor Cleve and J.L. Soret in Switzerland in 1879. The name homium 

-  -- comes from the Greek word Holmia which means Sweden. While all holmium 

-  -- compounds should be considered highly toxic, initial evidence seems to 

-  -- indicate that they do not pose much danger. The metal's dust however, is 

-  -- a fire hazard.

-  fun Holmium : Class ;

-  fun Holmium_Class : SubClass Holmium ElementalSubstance ;

-

-  -- Colourless, odourless gaseous chemical element. 

-  -- Lightest and most abundant element in the universe. Present in water and 

-  -- in all organic compounds. Chemically reacts with most elements. 

-  -- Discovered by Henry Cavendish in 1776.

-  fun Hydrogen : Class ;

-  fun Hydrogen_Class : SubClass Hydrogen ElementalSubstance ;

-

-  -- Soft silvery element belonging to group 13 of the 

-  -- periodic table. The most common natural isotope is In_115, which has a 

-  -- half_life of 6*10^4 years. Five other radioisotopes exist. Discovered in 

-  -- 1863 by Reich and Richter.

-  fun Indium : Class ;

-  fun Indium_Class : SubClass Indium ElementalSubstance ;

-

-  -- Dark violet nonmetallic element, belongs to group 

-  -- 17 of the periodic table. Insoluble in water. Required as a trace 

-  -- element for living organisms. One stable isotope, I_127 exists, in 

-  -- addition to fourteen radioactive isotopes. Chemically the least reactive 

-  -- of the halogens, and the most electropositive metallic halogen. 

-  -- Discovered in 1812 by Courtois.

-  fun Iodine : Class ;

-  fun Iodine_Class : SubClass Iodine ElementalSubstance ;

-

-  -- Very hard and brittle, silvery metallic transition 

-  -- element. It has a yellowish cast to it. Salts of iridium are highly 

-  -- colored. It is the most corrosion resistant metal known, not attacked by 

-  -- any acid, but is attacked by molten salts. There are two natural isotopes 

-  -- of iridium, and 4 radioisotopes, the most stable being Ir_192 with a 

-  -- half_life of 73.83 days. Ir_192 decays into {platinum}, while the other 

-  -- radioisotopes decay into {osmium}. Iridium is used in high temperature 

-  -- apparatus, electrical contacts, and as a hardening agent for platinum. 

-  -- Discovered in 1803 by Smithson Tennant in England. The name comes from 

-  -- the Greek word iris, which means rainbow. Iridium metal is generally 

-  -- non_toxic due to its relative unreactivity, but iridium compounds should 

-  -- be considered highly toxic.

-  fun Iridium : Class ;

-  fun Iridium_Class : SubClass Iridium ElementalSubstance ;

-

-  -- Silvery malleable and ductile metallic transition 

-  -- element. Has nine isotopes and is the fourth most abundant element in the 

-  -- earth's crust. Required by living organisms as a trace element (used in 

-  -- hemoglobin in humans.) Quite reactive, oxidizes in moist air, displaces 

-  -- hydrogen from dilute acids and combines with nonmetallic elements.

-  fun Iron : Class ;

-  fun Iron_Class : SubClass Iron ElementalSubstance ;

-

-  -- Colorless gaseous element, belongs to the noble 

-  -- gases. Occurs in the air, 0.0001 percent by volume. It can be extracted 

-  -- from liquid air by fractional distillation. Generally not isolated, but 

-  -- used with other inert gases in fluorescent lamps. Five natural isotopes, 

-  -- and five radioactive isotopes. Kr_85, the most stable radioactive 

-  -- isotope, has a half_life of 10.76 years and is produced in fission 

-  -- reactors. Practically inert, though known to form compounds with 

-  -- {fluorine}.

-  fun Krypton : Class ;

-  fun Krypton_Class : SubClass Krypton ElementalSubstance ;

-

-  -- (From the Greek word lanthanein, to line hidden) 

-  -- Silvery metallic element belonging to group 3 of the periodic table and 

-  -- oft considered to be one of the lanthanoids. Found in some rare_earth 

-  -- minerals. Twenty_five natural isotopes exist. La_139 which is stable, 

-  -- and La_138 which has a half_life of 10^10 to 10^15 years. The other 

-  -- twenty_three isotopes are radioactive. It resembles the lanthanoids 

-  -- chemically. Lanthanum has a low to moderate level of toxicity, and should 

-  -- be handled with care. Discovered in 1839 by C.G. Mosander.

-  fun Lanthanum : Class ;

-  fun Lanthanum_Class : SubClass Lanthanum ElementalSubstance ;

-

-  -- Appearance unknown, however it is most likely 

-  -- silvery_white or grey and metallic. Lawrencium is a synthetic rare_earth 

-  -- metal. There are eight known radioisotopes, the most stable being Lr_262 

-  -- with a half_life of 3.6 hours. Due to the short half_life of lawrencium, 

-  -- and its radioactivity, there are no known uses for it. Identified by 

-  -- Albert Ghiorso in 1961 at Berkeley. It was produced by bombarding 

-  -- californium with boron ions. The name is temporary {IUPAC} nomenclature, 

-  -- the origin of the name comes from Ernest O. Lawrence, the inventor of the 

-  -- cyclotron. If sufficient amounts of lawrencium were produced, it would 

-  -- pose a radiation hazard.

-  fun Lawrencium : Class ;

-  fun Lawrencium_Class : SubClass Lawrencium ElementalSubstance ;

-

-  -- Heavy dull grey ductile metallic element, belongs to 

-  -- group 14. Used in building construction, lead_place accumulators, bullets 

-  -- and shot, and is part of solder, pewter, bearing metals, type metals and 

-  -- fusible alloys.

-  fun Lead : Class ;

-  fun Lead_Class : SubClass Lead ElementalSubstance ;

-

-  -- Socket silvery metal. First member of group 1 of 

-  -- the periodic table. Lithium salts are used in psychomedicine.

-  fun Lithium : Class ;

-  fun Lithium_Class : SubClass Lithium ElementalSubstance ;

-

-  -- Silvery_white rare_earth metal which is 

-  -- relatively stable in air. It happens to be the most expensive rare_earth 

-  -- metal. Its found with almost all rare_earth metals, but is very difficult 

-  -- to separate from other elements. Least abundant of all natural elements. 

-  -- Used in metal alloys, and as a catalyst in various processes. There are 

-  -- two natural, stable isotopes, and seven radioisotopes, the most stable 

-  -- being Lu_174 with a half_life of 3.3 years. The separation of lutetium 

-  -- from {ytterbium} was described by Georges Urbain in 1907. It was 

-  -- discovered at approximately the same time by Carl Auer von Welsbach. The 

-  -- name comes from the Greek word lutetia which means Paris.

-  fun Lutetium : Class ;

-  fun Lutetium_Class : SubClass Lutetium ElementalSubstance ;

-

-  -- Silvery metallic element belonging to group 2 of 

-  -- the periodic table (alkaline_earth metals). It is essential for living 

-  -- organisms, and is used in a number of light alloys. Chemically very 

-  -- reactive, it forms a protective oxide coating when exposed to air and 

-  -- burns with an intense white flame. It also reacts with sulphur, nitrogen 

-  -- and the halogens. First isolated by Bussy in 1828.

-  fun Magnesium : Class ;

-  fun Magnesium_Class : SubClass Magnesium ElementalSubstance ;

-

-  -- Grey brittle metallic transition element. 

-  -- Rather electropositive, combines with some non_metals when heated. 

-  -- Discovered in 1774 by Scheele.

-  fun Manganese : Class ;

-  fun Manganese_Class : SubClass Manganese ElementalSubstance ;

-

-  -- Half_life of approximately 5ms. The creation 

-  -- of this element demonstrated that fusion techniques could indeed be used 

-  -- to make new, heavy nuclei. Made and identified by physicists of the Heavy 

-  -- Ion Research Laboratory, Darmstadt, West Germany in 1982. Named in honor 

-  -- of Lise Meitner the Austrian physicist.

-  fun Meitnerium : Class ;

-  fun Meitnerium_Class : SubClass Meitnerium ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element. 

-  -- Belongs to the actinoid series. Only known isotope, Md_256 has a 

-  -- half_life of 1.3 hours. First identified by Glenn T. Seaborg, Albert 

-  -- Ghiorso and associates in 1955. Alternative name {unnilunium} has been 

-  -- proposed. Named after the 'inventor' of the periodic table, Dmitri 

-  -- Mendeleev.

-  fun Mendelevium : Class ;

-  fun Mendelevium_Class : SubClass Mendelevium ElementalSubstance ;

-

-  -- Heavy silvery liquid metallic element, belongs to 

-  -- the zinc group. Used in thermometers, barometers and other scientific 

-  -- apparatus. Less reactive than zinc and cadmium, does not displace 

-  -- hydrogen from acids. Forms a number of complexes and organomercury 

-  -- compounds.

-  fun Mercury : Class ;

-  fun Mercury_Class : SubClass Mercury ElementalSubstance ;

-

-  -- Silvery_white, hard metallic transition 

-  -- element. It is chemically unreactive and is not affected by most acids. 

-  -- It oxidizes at high temperatures. There are seven natural isotopes, and 

-  -- four radioisotopes, Mo_93 being the most stable with a half_life of 3500 

-  -- years. Molybdenum is used in almost all high_strength steels, it has 

-  -- nuclear applications, and is a catalyst in petroleum refining. Discovered 

-  -- in 1778 by Carl Welhelm Scheele of Sweden. Impure metal was prepared in 

-  -- 1782 by Peter Jacob Hjelm. The name comes from the Greek word molybdos 

-  -- which means lead. Trace amounts of molybdenum are required for all known 

-  -- forms of life. All molybdenum compounds should be considered highly 

-  -- toxic, and will also cause severe birth defects.

-  fun Molybdenum : Class ;

-  fun Molybdenum_Class : SubClass Molybdenum ElementalSubstance ;

-

-  -- Soft bright silvery metallic element, belongs to 

-  -- the lanthanoids. Seven natural isotopes, Nd_144 being the only 

-  -- radioactive one with a half_life of 10^10 to 10^15 years. Six artificial 

-  -- radioisotopes have been produced. The metal is used in glass works to 

-  -- color class a shade of violet_purple and make it dichroic. One of the 

-  -- more reactive rare_earth metals, quickly reacts with air. Used in some 

-  -- rare_earth alloys. Neodymium is used to color the glass used in welder's 

-  -- glasses. Neodymium is also used in very powerful, permanent magnets 

-  -- (Nd2Fe14B). Discovered by Carl F. Auer von Welsbach in Austria in 1885 

-  -- by separating didymium into its elemental components {praseodymium} and 

-  -- neodymium. The name comes from the Greek words 'neos didymos' which means 

-  -- 'new twin'. Neodymium should be considered highly toxic, however evidence 

-  -- would seem to show that it acts as little more than a skin and eye 

-  -- irritant. The dust however, presents a fire and explosion hazard.

-  fun Neodymium : Class ;

-  fun Neodymium_Class : SubClass Neodymium ElementalSubstance ;

-

-  -- Colourless gaseous element of group 18 on the 

-  -- periodic table (noble gases). Neon occurs in the atmosphere, and 

-  -- comprises 0.0018 percent of the volume of the atmosphere. It has a 

-  -- distinct reddish glow when used in discharge tubes and neon based lamps. 

-  -- It forms almost no chemical compounds. Neon was discovered in 1898 by Sir 

-  -- William Ramsey and M.W. Travers.

-  fun Neon : Class ;

-  fun Neon_Class : SubClass Neon ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element, 

-  -- belongs to the actinoids. Np_237, the most stable isotope, has a 

-  -- half_life of 2.2*10^6 years and is a by product of nuclear reactors. The 

-  -- other known isotopes have mass numbers 229 through 236, and 238 through 

-  -- 241. Np_236 has a half_life of 5*10^3 years. First produced by Edwin M. 

-  -- McMillan and P.H. Abelson in 1940.

-  fun Neptunium : Class ;

-  fun Neptunium_Class : SubClass Neptunium ElementalSubstance ;

-

-  -- Malleable ductile silvery metallic transition 

-  -- element. Discovered by A.F. Cronstedt in 1751.

-  fun Nickel : Class ;

-  fun Nickel_Class : SubClass Nickel ElementalSubstance ;

-

-  -- Soft, ductile grey_blue metallic transition 

-  -- element. Used in special steels and in welded joints to increase 

-  -- strength. Combines with halogens and oxidizes in air at 200 degrees 

-  -- celsius. Discovered by Charles Hatchett in 1801 and isolated by 

-  -- Blomstrand in 1864. Called {columbium} originally.

-  fun Niobium : Class ;

-  fun Niobium_Class : SubClass Niobium ElementalSubstance ;

-

-  -- Colourless, gaseous element which belongs to 

-  -- group 15 of the periodic table. Constitutes ~78 percent of the atmosphere 

-  -- and is an essential part of the ecosystem. Nitrogen for industrial 

-  -- purposes is acquired by the fractional distillation of liquid air. 

-  -- Chemically inactive, reactive generally only at high temperatures or in 

-  -- electrical discharges. It was discovered in 1772 by D. Rutherford.

-  fun Nitrogen : Class ;

-  fun Nitrogen_Class : SubClass Nitrogen ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element, belongs 

-  -- to the actinoids. Seven known isotopes exist, the most stable being 

-  -- No_254 with a half_life of 255 seconds. First identified with certainty 

-  -- by Albert Ghiorso and Glenn T. Seaborg in 1966. {Unnilbium} has been 

-  -- proposed as an alternative name.

-  fun Nobelium : Class ;

-  fun Nobelium_Class : SubClass Nobelium ElementalSubstance ;

-

-  -- Hard blue_white metallic transition element. Found 

-  -- with platinum and used in some alloys with platinum and iridium.

-  fun Osmium : Class ;

-  fun Osmium_Class : SubClass Osmium ElementalSubstance ;

-

-  -- A colourless, odourless gaseous element belonging 

-  -- to group 16 of the periodic table. It is the most abundant element 

-  -- present in the earth's crust. It also makes up 20.8 percent of the 

-  -- Earth's atmosphere. For industrial purposes, it is separated from liquid 

-  -- air by fractional distillation. It is used in high temperature welding, 

-  -- and in breathing. It commonly comes in the form of Oxygen, but is found 

-  -- as Ozone in the upper atmosphere. It was discovered by Priestley in 

-  -- 1774.

-  fun Oxygen : Class ;

-  fun Oxygen_Class : SubClass Oxygen ElementalSubstance ;

-

-  -- Soft white ductile transition element. Found 

-  -- with some copper and nickel ores. Does not react with oxygen at normal 

-  -- temperatures. Dissolves slowly in hydrochloric acid. Discovered in 1803 

-  -- by W.H. Wollaston.

-  fun Palladium : Class ;

-  fun Palladium_Class : SubClass Palladium ElementalSubstance ;

-

-  -- Non_metallic element belonging to group 15 of 

-  -- the periodic table. Has a multiple allotropic forms. Essential element 

-  -- for living organisms. It was discovered by Brandt in 1669.

-  fun Phosphorus : Class ;

-  fun Phosphorus_Class : SubClass Phosphorus ElementalSubstance ;

-

-  -- Attractive greyish_white metal. When pure, it is 

-  -- malleable and ductile. Does not oxidize in air, insoluble in hydrochloric 

-  -- and nitric acid. Corroded by halogens, cyandies, sulphur and alkalis. 

-  -- {Hydrogen} and {oxygen} react explosively in the presence of platinum. 

-  -- There are six stable isotopes and three radioisotopes, the most stable 

-  -- being Pt_193 with a half_life of 60 years. Platinum is used in jewelry, 

-  -- laboratory equipment, electrical contacts, dentistry, and anti_pollution 

-  -- devices in cars. PtCl2(NH3)2 is used to treat some forms of cancer. 

-  -- Platinum_{cobalt} alloys have magnetic properties. It is also used in the 

-  -- definition of the Standard Hydrogen Electrode. Discovered by Antonio de 

-  -- Ulloa in South America in 1735. The name comes from the Spanish word 

-  -- platina which means silver. Platinum metal is generally not a health 

-  -- concern due to its unreactivity, however platinum compounds should be 

-  -- considered highly toxic.

-  fun Platinum : Class ;

-  fun Platinum_Class : SubClass Platinum ElementalSubstance ;

-

-  -- Dense silvery radioactive metallic transuranic 

-  -- element, belongs to the actinoids. Pu_244 is the most stable isotope with 

-  -- a half_life of 7.6*10^7 years. Thirteen isotopes are known. Pu_239 is 

-  -- the most important, it undergoes nuclear fission with slow neutrons and is 

-  -- hence important to nuclear weapons and reactors. Plutonium production is 

-  -- monitored down to the gram to prevent military misuse. First produced by 

-  -- Gleen T. Seaborg, Edwin M. McMillan, J.W. Kennedy and A.C. Wahl in 

-  -- 1940.

-  fun Plutonium : Class ;

-  fun Plutonium_Class : SubClass Plutonium ElementalSubstance ;

-

-  -- Rare radioactive metallic element, belongs to 

-  -- group 16 of the periodic table. Over 30 known isotopes exist, the most of 

-  -- all elements. Po_209 has a half_life of 103 years. Possible uses in 

-  -- heating spacecraft. Discovered by Marie Curie in 1898 in a sample of 

-  -- pitchblende.

-  fun Polonium : Class ;

-  fun Polonium_Class : SubClass Polonium ElementalSubstance ;

-

-  -- Soft silvery metallic element belonging to group 

-  -- 1 of the periodic table (alkali metals). Occurs naturally in seawater and 

-  -- a many minerals. Highly reactive, chemically, it resembles sodium in its 

-  -- behavior and compounds. Discovered by Sir Humphry Davy in 1807.

-  fun Potassium : Class ;

-  fun Potassium_Class : SubClass Potassium ElementalSubstance ;

-

-  -- Soft silvery metallic element, belongs to the 

-  -- lanthanoids. Only natural isotope is Pr_141 which is not radioactive. 

-  -- Fourteen radioactive isotopes have been artificially produced. Used in 

-  -- rare_earth alloys. Discovered in 1885 by C.A. von Welsbach.

-  fun Praseodymium : Class ;

-  fun Praseodymium_Class : SubClass Praseodymium ElementalSubstance ;

-

-  -- Soft silvery metallic element, belongs to the 

-  -- lanthanoids. Pm_147, the only natural isotope, is radioactive and has a 

-  -- half_life of 252 years. Eighteen radioisotopes have been produced, but 

-  -- all have very short half_lives. Found only in nuclear decay waste. 

-  -- Pm_147 is of interest as a beta_decay source, however Pm_146 and Pm_148 

-  -- have to be removed from it first, as they generate gamma radiation. 

-  -- Discovered by J.A. Marinsky, L.E. Glendenin and C.D. Coryell in 

-  -- 1947.

-  fun Promethium : Class ;

-  fun Promethium_Class : SubClass Promethium ElementalSubstance ;

-

-  -- Radioactive metallic element, belongs to the 

-  -- actinoids. The most stable isotope, Pa_231 has a half_life of 2.43*10^4 

-  -- years. At least 10 other radioactive isotopes are known. No practical 

-  -- applications are known. Discovered in 1917 by Lise Meitner and Otto 

-  -- Hahn.

-  fun Protactinium : Class ;

-  fun Protactinium_Class : SubClass Protactinium ElementalSubstance ;

-

-  -- Radioactive metallic transuranic element, belongs 

-  -- to group 2 of the periodic table. Most stable isotope, Ra_226 has a 

-  -- half_life of 1602 years, which decays into radon. Isolated from 

-  -- pitchblende in 1898 Marie and Pierre Curie.

-  fun Radium : Class ;

-  fun Radium_Class : SubClass Radium ElementalSubstance ;

-

-  -- Colorless radioactive gaseous element, belongs to 

-  -- the noble gases. Of the twenty known isotopes, the most stable is Rn_222 

-  -- with a half_life of 3.8 days. Formed by the radioactive decay of 

-  -- {Radium}_226. Radon itself decays into {polonium}. Used in radiotherapy. 

-  -- As a noble gas, it is effectively inert, though radon fluoride has been 

-  -- synthesized. First isolated in 1908 by Ramsey and Gray.

-  fun Radon : Class ;

-  fun Radon_Class : SubClass Radon ElementalSubstance ;

-

-  -- Silvery_white metallic transition element. 

-  -- Obtained as a by_product of molybdenum refinement. Rhenium_molybdenum 

-  -- alloys are superconducting.

-  fun Rhenium : Class ;

-  fun Rhenium_Class : SubClass Rhenium ElementalSubstance ;

-

-  -- Silvery white metallic transition element. Found 

-  -- with platinum and used in some platinum alloys. Not attacked by acids, 

-  -- dissolves only in aqua regia. Discovered in 1803 by W.H. Wollaston.

-  fun Rhodium : Class ;

-  fun Rhodium_Class : SubClass Rhodium ElementalSubstance ;

-

-  -- Soft silvery metallic element, belongs to group 1 

-  -- of the periodic table. Rb_97, the naturally occurring isotope, is 

-  -- radioactive. It is highly reactive, with properties similar to other 

-  -- elements in group 1, like igniting spontaneously in air. Discovered 

-  -- spectroscopically in 1861 by W. Bunsen and G.R. Kirchoff.

-  fun Rubidium : Class ;

-  fun Rubidium_Class : SubClass Rubidium ElementalSubstance ;

-

-  -- Hard white metallic transition element. Found 

-  -- with platinum, used as a catalyst in some platinum alloys. Dissolves in 

-  -- fused alkalis, and is not attacked by acids. Reacts with halogens and 

-  -- oxygen at high temperatures. Isolated in 1844 by K.K. Klaus.

-  fun Ruthenium : Class ;

-  fun Ruthenium_Class : SubClass Ruthenium ElementalSubstance ;

-

-  -- Soft silvery metallic element, belongs to the 

-  -- lanthanoids. Seven natural isotopes, Sm_147 is the only radioisotope, and 

-  -- has a half_life of 2.5*10^11 years. Used for making special alloys needed 

-  -- in the production of nuclear reactors. Also used as a neutron absorber. 

-  -- Small quantities of samarium oxide is used in special optical glasses. 

-  -- The largest use of the element is its ferromagnetic alloy which produces 

-  -- permanent magnets that are five times stronger than magnets produced by 

-  -- any other material. Discovered by Francois Lecoq de Boisbaudran in 

-  -- 1879.

-  fun Samarium : Class ;

-  fun Samarium_Class : SubClass Samarium ElementalSubstance ;

-

-  -- Rare soft silvery metallic element belonging to 

-  -- group 3 of the periodic table. There are ten isotopes, nine of which are 

-  -- radioactive and have short half_lives. Predicted in 1869 by Mendeleev, 

-  -- isolated by Nilson in 1879.

-  fun Scandium : Class ;

-  fun Scandium_Class : SubClass Scandium ElementalSubstance ;

-

-  -- Metalloid element, belongs to group 16 of the 

-  -- periodic table. Multiple allotropic forms exist. Chemically resembles 

-  -- sulphur. Discovered in 1817 by Jons J. Berzelius.

-  fun Selenium : Class ;

-  fun Selenium_Class : SubClass Selenium ElementalSubstance ;

-

-  -- Metalloid element belonging to group 14 of the 

-  -- periodic table. It is the second most abundant element in the Earth's 

-  -- crust, making up 25.7 percent of it by weight. Chemically less reactive 

-  -- than carbon. First identified by Lavoisier in 1787 and first isolated in 

-  -- 1823 by Berzelius.

-  fun Silicon : Class ;

-  fun Silicon_Class : SubClass Silicon ElementalSubstance ;

-

-  -- White lustrous soft metallic transition element. 

-  -- Found in both its elemental form and in minerals. Used in jewellery, 

-  -- tableware and so on. Less reactive than silver, chemically.

-  fun Silver : Class ;

-  fun Silver_Class : SubClass Silver ElementalSubstance ;

-

-  -- Soft silvery reactive element belonging to group 1 

-  -- of the periodic table (alkali metals). It is highly reactive, oxidizing 

-  -- in air and reacting violently with water, forcing it to be kept under oil. 

-  -- It was first isolated by Humphrey Davy in 1807.

-  fun Sodium : Class ;

-  fun Sodium_Class : SubClass Sodium ElementalSubstance ;

-

-  -- Soft yellowish metallic element, belongs to 

-  -- group 2 of the periodic table. Highly reactive chemically. Sr_90 is 

-  -- present in radioactive fallout and has a half_life of 28 years. 

-  -- Discovered in 1798 by Klaproth and Hope, isolated in 1808 by Humphry 

-  -- Davy.

-  fun Strontium : Class ;

-  fun Strontium_Class : SubClass Strontium ElementalSubstance ;

-

-  -- Yellow, nonmetallic element belonging to group 16 

-  -- of the periodic table. It is an essential element in living organisms, 

-  -- needed in the amino acids cysteine and methionine, and hence in many 

-  -- proteins. Absorbed by plants from the soil as sulphate ion.

-  fun Sulphur : Class ;

-  fun Sulphur_Class : SubClass Sulphur ElementalSubstance ;

-

-  -- Heavy blue_grey metallic transition element. 

-  -- Ta_181 is a stable isotope, and Ta_180 is a radioactive isotope, with a 

-  -- half_life in excess of 10^7 years. Used in surgery as it is unreactive. 

-  -- Forms a passive oxide layer in air. Identified in 1802 by Ekeberg and 

-  -- isolated in 1820 by Jons J. Berzelius.

-  fun Tantalum : Class ;

-  fun Tantalum_Class : SubClass Tantalum ElementalSubstance ;

-

-  -- Radioactive metallic transition element. Can 

-  -- be detected in some stars and the fission products of uranium. First made 

-  -- by Perrier and Segre by bombarding molybdenum with deutrons, giving them 

-  -- Tc_97. Tc_99 is the most stable isotope with a half_life of 2.6*10^6 

-  -- years. Sixteen isotopes are known. Organic technetium compounds are used 

-  -- in bone imaging. Chemical properties are intermediate between rhenium and 

-  -- manganese.

-  fun Technetium : Class ;

-  fun Technetium_Class : SubClass Technetium ElementalSubstance ;

-

-  -- Silvery metalloid element of group 16. Eight 

-  -- natural isotopes, nine radioactive isotopes. Used in semiconductors and 

-  -- to a degree in some steels. Chemistry is similar to {sulphur}. 

-  -- Discovered in 1782 by Franz Miller.

-  fun Tellurium : Class ;

-  fun Tellurium_Class : SubClass Tellurium ElementalSubstance ;

-

-  -- Silvery metallic element belonging to the 

-  -- lanthanoids. Tb_159 is the only stable isotope, there are seventeen 

-  -- artificial isotopes. Discovered by G.G. Mosander in 1843.

-  fun Terbium : Class ;

-  fun Terbium_Class : SubClass Terbium ElementalSubstance ;

-

-  -- Pure, unreacted thallium appears silvery_white 

-  -- and exhibits a metallic lustre. Upon reacting with air, it begins to turn 

-  -- bluish_grey and looks like lead. It is very malleable, and can be cut 

-  -- with a knife. There are two stable isotopes, and four radioisotopes, 

-  -- Tl_204 being the most stable with a half_life of 3.78 years. Thallium 

-  -- sulphate was used as a rodenticide. Thallium sulphine's conductivity 

-  -- changes with exposure to infrared light, this gives it a use in infrared 

-  -- detectors. Discovered by Sir William Crookes via spectroscopy. Its name 

-  -- comes from the Greek word thallos, which means green twig. Thallium and 

-  -- its compounds are toxic and can cause cancer.

-  fun Thallium : Class ;

-  fun Thallium_Class : SubClass Thallium ElementalSubstance ;

-

-  -- Grey radioactive metallic element. Belongs to 

-  -- actinoids. Found in monazite sand in Brazil, India and the US. 

-  -- Thorium_232 has a half_life of 1.39x10^10 years. Can be used as a nuclear 

-  -- fuel for breeder reactors. Thorium_232 captures slow {neutron}s and 

-  -- breeds uranium_233. Discovered by Jons J. Berzelius in 1829.

-  fun Thorium : Class ;

-  fun Thorium_Class : SubClass Thorium ElementalSubstance ;

-

-  -- Soft grey metallic element that belongs to the 

-  -- lanthanoids. One natural isotope exists, Tm_169, and seventeen artificial 

-  -- isotopes have been produced. No known uses for the element. Discovered 

-  -- in 1879 by Per Theodor Cleve.

-  fun Thulium : Class ;

-  fun Thulium_Class : SubClass Thulium ElementalSubstance ;

-

-  -- Silvery malleable metallic element belonging to group 

-  -- 14 of the periodic table. Twenty_six isotopes are known, five of which 

-  -- are radioactive. Chemically reactive. Combines directly with chlorine 

-  -- and oxygen and displaces hydrogen from dilute acids.

-  fun Tin : Class ;

-  fun Tin_Class : SubClass Tin ElementalSubstance ;

-

-  -- White metallic transition element. Occurs in 

-  -- numerous minerals. Used in strong, light corrosion_resistant alloys. 

-  -- Forms a passive oxide coating when exposed to air. First discovered by 

-  -- Gregor in 1789.

-  fun Titanium : Class ;

-  fun Titanium_Class : SubClass Titanium ElementalSubstance ;

-

-  -- White or grey metallic transition element, 

-  -- formerly called {wolfram}. Forms a protective oxide in air and can be 

-  -- oxidized at high temperature. First isolated by Jose and Fausto de 

-  -- Elhuyer in 1783.

-  fun Tungsten : Class ;

-  fun Tungsten_Class : SubClass Tungsten ElementalSubstance ;

-

-  -- Half_life of approximately 10ms. Reported in 

-  -- 1994 by German researchers at Darmstadt, Germany.

-  fun Unnildecium : Class ;

-  fun Unnildecium_Class : SubClass Unnildecium ElementalSubstance ;

-

-  -- Half_life of 0.9 +/_ 0.2 s. Discovered by the 

-  -- Joint Institute for Nuclear Research at Dubna (U.S.S.R.) in June of 1974. 

-  -- Its existence was confirmed by the Lawrence Berkeley Laboratory and 

-  -- Livermore National Laboratory in September of 1974.

-  fun Unnilhexium : Class ;

-  fun Unnilhexium_Class : SubClass Unnilhexium ElementalSubstance ;

-

-  -- Radioactive transition metal.

-  fun Unniloctium : Class ;

-  fun Unniloctium_Class : SubClass Unniloctium ElementalSubstance ;

-

-  -- Radioactive transactinide element. Half_life 

-  -- of 1.6s. Discovered in 1970 by Berkeley researchers. So far, seven 

-  -- isotopes have been discovered.

-  fun Unnilpentium : Class ;

-  fun Unnilpentium_Class : SubClass Unnilpentium ElementalSubstance ;

-

-  -- Radioactive transactinide element. Expected 

-  -- to have similar chemical properties to those displayed by hafnium. Rf_260 

-  -- was discovered by the Joint Nuclear Research Institute at Dubna (U.S.S.R.) 

-  -- in 1964. Researchers at Berkeley discovered Unq_257 and Unq_258 in 

-  -- 1964.

-  fun Unnilquadium : Class ;

-  fun Unnilquadium_Class : SubClass Unnilquadium ElementalSubstance ;

-

-  -- Radioactive transition metal. Half_life of 

-  -- approximately 1/500 s. Discovered by the Joint Institute for Nuclear 

-  -- Research at Dubna (U.S.S.R.) in 1976. Confirmed by West German physicists 

-  -- at the Heavy Ion Research Laboratory at Darmstadt.

-  fun Unnilseptium : Class ;

-  fun Unnilseptium_Class : SubClass Unnilseptium ElementalSubstance ;

-

-  -- White radioactive metallic element belonging to 

-  -- the actinoids. Three natural isotopes, U_238, U_235 and U_234. 

-  -- Uranium_235 is used as the fuel for nuclear reactors and weapons. 

-  -- Discovered by Martin H. Klaproth in 1789.

-  fun Uranium : Class ;

-  fun Uranium_Class : SubClass Uranium ElementalSubstance ;

-

-  -- Soft and ductile, bright white metal. Good 

-  -- resistance to corrosion by alkalis, sulphuric and hydrochloric acid. It 

-  -- oxidizes readily about 933K. There are two naturally occurring isotopes 

-  -- of vanadium, and 5 radioisotopes, V_49 having the longest half_life at 337 

-  -- days. Vanadium has nuclear applications, the foil is used in cladding 

-  -- titanium to steel, and vanadium_gallium tape is used to produce a 

-  -- superconductive magnet. Originally discovered by Andres Manuel del Rio of 

-  -- Mexico City in 1801. His discovery went unheeded, however, and in 1820, 

-  -- Nils Gabriel Sefstron of Sweden rediscovered it. Metallic vanadium was 

-  -- isolated by Henry Enfield Roscoe in 1867. The name vanadium comes from 

-  -- {Vanadis}, a goddess of Scandinavian mythology. Silvery_white metallic 

-  -- transition element. Vanadium is essential to {ascidian}s. Rats and 

-  -- chickens are also known to require it. Metal powder is a fire hazard, and 

-  -- vanadium compounds should be considered highly toxic. May cause lung 

-  -- cancer if inhaled.

-  fun Vanadium : Class ;

-  fun Vanadium_Class : SubClass Vanadium ElementalSubstance ;

-

-  -- Colourless, odourless gas belonging to group 18 on 

-  -- the periodic table (the noble gases.) Nine natural isotopes and seven 

-  -- radioactive isotopes are known. Xenon was part of the first noble_gas 

-  -- compound synthesized. Several others involving Xenon have been found 

-  -- since then. Xenon was discovered by Ramsey and Travers in 1898.

-  fun Xenon : Class ;

-  fun Xenon_Class : SubClass Xenon ElementalSubstance ;

-

-  -- Silvery metallic element of the lanthanoids. 

-  -- Seven natural isotopes and ten artificial isotopes are known. Used in 

-  -- certain steels. Discovered by J.D.G. Marignac in 1878.

-  fun Ytterbium : Class ;

-  fun Ytterbium_Class : SubClass Ytterbium ElementalSubstance ;

-

-  -- Silvery_grey metallic element of group 3 on the 

-  -- periodic table. Found in uranium ores. The only natural isotope is Y_89, 

-  -- there are 14 other artificial isotopes. Chemically resembles the 

-  -- lanthanoids. Stable in the air below 400 degrees, celsius. Discovered in 

-  -- 1828 by Friedrich Wohler.

-  fun Yttrium : Class ;

-  fun Yttrium_Class : SubClass Yttrium ElementalSubstance ;

-

-  -- Blue_white metallic element. Occurs in multiple 

-  -- compounds naturally. Five stable isotopes are six radioactive isotopes 

-  -- have been found. Chemically a reactive metal, combines with oxygen and 

-  -- other non_metals, reacts with dilute acids to release hydrogen.

-  fun Zinc : Class ;

-  fun Zinc_Class : SubClass Zinc ElementalSubstance ;

-

-  -- Grey_white metallic transition element. Five 

-  -- natural isotopes and six radioactive isotopes are known. Used in nuclear 

-  -- reactors for a {neutron} absorber. Discovered in 1789 by Martin Klaproth, 

-  -- isolated in 1824 by Berzelius.

-  fun Zirconium : Class ;

-  fun Zirconium_Class : SubClass Zirconium ElementalSubstance ;

-

-}