TELLURIUM

Te. Atomic weight 127.5. An element belonging to the oxygen-sulphur family. It is on the borderline between the metals and non-metals, the oxide acting both as an acid and as a base. It occurs asa black or dark grey powder or as a grey solid with a metallic lustre. It is widely distributed in the earth’s crust but does not occur abundantly. It is found in small quantities a ociated with gold, silver and bismuth ores. It received its name in 1798, but was recognized many years prior to that date. It has a specific gravity of about 6.0 and melts at 452°-454° C. It is soluble in sulphuric and nitric acids, and in pota ium hydroxide but is insoluble in water. It is used in ceramics and in medicine.