Physics

Antimony Definition Antimony is a metalloid element having many forms, the most common of which is a hard, very brittle, shiny, blue-white crystal. Antimony compounds…

Neptunium Definition Neptunium is a silvery, radioactive metallic element of the actinide series. It occurs naturally in minute amounts in uranium ores and is produced…

About Plutonium Definition Plutonium is a silvery, radioactive metallic element of the actinide series that has the highest atomic number of all naturally occurring elements.…

Indium Definition Indium is a soft, malleable, silvery-white metallic element that occurs mainly in ores of zinc and lead. Its atomic number 49; atomic weight…

Gallium Definition Gallium is a rare, silvery metallic element that is found as a trace element in coal, in bauxite, and in several minerals. It…

Mercury Definition Mercury is a silvery-white, dense, poisonous metallic element that is a liquid at room temperature and is used in thermometers, barometers, batteries, and…

Uranium Definition Uranium is a heavy, silvery-white, highly toxic, radioactive metallic element of the actinide series. It has 14 known isotopes, of which U 238…

Erbium Definition Erbium is a soft malleable silvery-white element of the lanthanide series of metals: used in special alloys, room-temperature lasers, and as a pigment.…

Xenotime Definition Xenotime is a phosphate mineral, similar to monazite except enriched in the heavy lanthanides and yttrium. It is a rare earth phosphate mineral.…

Terbium Definition Terbium is a soft, silvery-gray metallic element of the lanthanide series. It is used in color television tubes, x-ray machines, and lasers. Its…

Gadolinium Definition Gadolinium is a silvery-white, malleable, ductile metallic element of the lanthanide series that has seven natural isotopes and 11 artificial isotopes. It is…

Limonite Definition Limonite is a common brown, black, or yellow amorphous secondary mineral that consists of hydrated ferric oxides and is a source of iron.…