VANADIC ACID. [Vasanium.) VANAD1IThi (V). A rare metal. It was discovered in 1801 be Del Rio, and in 1830 named, by Sofstroni, Vanadium, from rantiis, a cognomen of the Scandinavian goddess Prcia. In exceedingly mffitito quantity it exists in nearly all clays, but occurs in abundance in a lead ore (vanadiatc of lead) found at Wanlockhead in Scotland, Zimapan in Mexico, and recently in Chili.
By reducing vanadic anhydride with potassium, and digesting the product in water, vanadium is obtained as a brilliant, metallic powder ; soluble in nitric acid or aqua regia, but unacted upon by boiling sul phuric, hydrochloric, or nitric acids.
The equivalent of vanadium is 63'48.
Vanadium and oxygen combine in three proportions. The protaxide (VO) has the appearance of graphite, and is formed when hydrogen is passed over heated vanadic acid. The binexide is a black powder produced when the protexide is heated in the air; it combines with acids to form salts, which have a blue colour. The to oxide or vanadic anhydride is a brownish-red powder that remains on heating bivanadiate of ammonia. It fuses at a red heat, and is slightly soluble in water, to which it communicates a yellow tint and an acid reaction.
ranadie acid (2 HO, falls as a precipitate when nitric acid is added to a hot solution of a bivanadiate; in appearance it much resembles hydrated oxide of iron. Dried over sulphuric acid it loses an equivalent of water, and protohydrate (HO, remains.
ranadiatcs are obtained on decomposing bivanadiate of ammonia by a chloride. They contain— To produce bivanadiate of ammonia Hauer recommends that the crude vanadium compound be calcined, the residue digested In water, the insoluble portion fused with nitrate of potash, the resulting mass digested in water, the solution concentrated, and vanadinte of ammonia precipitated by adding excess of chloride of ammonium ; it is purified by repeated crystallisation from water containing acetic acid.
Two chlorides (VCI, and well as sulphides, bromides, iodides, and fluorides of vanadium, have been obtained.
Testa for Vanadium. By reducing agents, such as sulphide of hydro gen, or a boiling mixture of sulphuric acid with alcohol or anger, vanatliates yield beautiful blue solutions. This reaction distinguishes them from chromates, which under the same circumstances give green liquids.