vanadium

[Latinized from Vanadis, a name of the Scand in avian godde Freyja, from the fact of its discovery in Swedish iron.] Chem.: A metallic pentad element, discovered by Sefstrom in 1830, in the refinery slag of the iron ores of Taberg, in Sweden; symbol, V; atomic weight, 51.2. It is extracted from the finely-pulverized slag by deflagrating with niter and sodic carbonate, digesting the fused ma with a saturated solution of sal-ammoniac, and igniting the product in an open ve el. On heating the ma with pota ium, and washing with water, pure vanadium is obtained as a brilliant metallic powder, having a silver-white luster. It is non-volatile, does not tarnish in the air, burns vividly when heated in oxygen, is insoluble in hydrochloric acid, di olves slowly in hydrofluoric acid, but very rapidly in nitric acid, forming a blue solution. It forms five oxides, analogous to the oxides of nitrogen, and three chlorides, viz., the dichloride, the trichloride, and the tetrachlo ride. vanadium-oxides, s. pl. Chem.: Vanadium forms four oxides: (1) Vanadium dioxide, V2O2, is obtained by reducing either of the higher oxides with pota ium. It forms a light-gray glittering powder, having a specific gravity of 364, and is insoluble in sulphuric and hydrochloric acids. (2) Vanadium trioxide, V2O3, is obtained by igniting the pentoxide in hydrogen gas. It is a black powder, with an almost metallic luster, and is insoluble in acids. (3) Vanadium tetroxide, V2O4, is obtained by allowing the trioxide to absorb oxygen at ordinary temperatures, forming blue shining crystals. It is soluble in acids, and combines with bases forming van a dites, none of which is of any importance. (4) Vanadium pentoxide, V2O5, is obtained by igniting vanadate of ammonium in an open platinum crucible. It has a more or le reddish-yellow color, is tastele , and di olves in the stronger acids, forming red or yellow solutions.