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Tellurium

element and acid

TELLURIUM, an element discovered by Mueller von Reichenstein (1782) in a specimen of gold ore from Austria. Klaproth named it from the Latin tellus, meaning the earth. Tel lurium occurs free, but most commonly in company with gold, silver, lead and bismuth. Native tellurium is found in considerable quantity in Boulder County, Colo. The other important minerals containing tellurium are sylvanite, calaverite, pelzite, hessite and tetra dymite. They are found principally in Aus tria, and in the United States in Colorado and adjacent States.

Tellurium is a silver white metal, atomic weight 127.6, melting point about 453 C. and specific gravity 6.25. It is brittle, not changed by exposure to the air and when heated a little above its melting point it boils and condenses again in the cool portion of the retort as metal lic drops. In chemical properties it is very like sulphur. It unites with chlorine readily,

forming and Teas. The oxides TeO, and Te02 are analogous, yet differ considerably from SO2 and SO2. Tellurious and telluric acids and the salts derived from them are also known. Tellurium forms a compound with hydrogen analogous to 112S and possessing an even more disagreeable odor.

This element resembles sulphur in impart ing very undesirable properties to metals even when present in very small amount. If tellu rium and any of its compounds are introduced into the human system they give the breath a very strong and disagreeable garlic-like odor. To obtain the free element the ore is digested first with sulphuric acid; hydrochloric acid is then added in small quantity and the whole treated with sulphurous acid which precipitates the tellurium.