Home >> Encyclopedia Americana, Volume 27 >> Van Dyck to Yaper >> Vanadium_P1


acid, vanadic, manufacture, found, free, powder and acids

Page: 1 2

VANADIUM. A rare element which, in its chemical behavior, is related to arsenic, phosphorus and nitrogen. Its symbol is V, its atomic weight 51.2 and its specific gravity 5.5. It was discovered by Seffstrom in 1830 and derives its name from the Scandinavian goddess Vanadis, who corresponds to Freya in the Teutonic mythology. It is never found free in nature but exists in combination, in small quantities, in copper, lead and iron ores, par ticularly the latter. It is contained in vanadinite (PbC1)P134(V0.)2, and decloisite (PbTn). (ON)VO4 and is extracted with great difficulty. It is widely diffused in nature, being found where deposits of copper, lead and iron are found. In the United States it has been ob tamed from the mineral deposits of Colorado, Utah and elsewhere. It may be reduced to a free state by heating vanadium dichloride in a stream of hydrogen and appears in the form of a silver colored crystalline powder. This powder is acted upon very slowly by the air at ordinary or even elevated temperatures. but it burns brightly and produces V.0, when ignited. It is soluble in nitric, hydrofluoric and con centrated sulphuric acids, but not in hydrochloric or dilute sulphuric acids. Vanadium forms three basic oxides V,O, V.O. and V.01, and two acid oxides V204 and V20,. The last of these is very important and appears as a red dish yellow powder, which dissolves freely in alkaline hydroxides or carbonates and forms salts which are known as vanadates. Three varieties of vanadates have thus far been com posed and they are known as ortho, pyro and metavanadates, the latter being the most stable of the three. The metavanadate of sodium is a salt of considerable importance. The vanadates carry oxygen in many chemical reactions. Vanadic acid is the most important and the best known of the compounds of vanadium. It is the final product of the oxidation of vana dium and bears to that element the same re lation which phosphoric arsenic and antimonic acids bear to their respective metals. Vanadic acid parts readily with its oxygen and receives it again as readily frcm other substances. Thus when vanadic acid is taken into the blood it is first converted into hypovanadic acid, but when it is subsequently combined with the ox yhmmoglobin of the blood it is raised to hyper vanadic acid. Metovanadic acid may exist in

free condition in the form of a beautiful golden yellow substance which is sometimes used as a substitute for gold bronze. Ammonium meta vanadate is used in the manufacture of the dye which is known as aniline black and also in the manufacture of vanadium ink. Thus while vanadium itself is a metal of no particular im portance technically, its various combinations have a very decided value from many points of view. In addition to the uses which were men tioned in the preceding paragraphs it is im portant to note the following: the pentoxide of vanadium is useful in photography as a de veloper, the chloride and the trioxide are used as mordants in the manufacture of print cloths, the trioxide is also employed in the manufacture of steel and in the composition of malleable and ductile alloys.

Vanadium has also been used to a moderate extent as a therapeutic agent, the pentoxide (hypervanadic acid) being given in diseases which are due to defective metabolism, but it is a substance in the use of which there may be decided danger and there does not seem to have been enough clinical evidence thus far to justify its frequent use. It is not mentioned in the list of approved medicinal substances which is to be found in the last edition of the United States pharmacopoeia. There are those, however, who advocate its use therapeutically among whom may be mentioned Laran, Lyonnet, Martz, Mar tin, Helouis and Delarne. The physiological action of vanadium salts has been investigated by Platt (Lancet, 15 Jan. 1876), by Gamgee and Larmuth (Journal of Anatomy II, 2, 1879) and by Priestley and Gamgee ((Philo sophical Transactions,' Vol. 166, p. 12). Robert and others ('Lehrbuch der Intoxikationen,' p. 309, 1893) have written in regard to its therapeutic action. Weber de clinique et de thirapic,' 1898) and Helouis and Delarne ('Congris pour l'etude de tuberculose,' p. 895, 1898, des comptes rendus et memoiree) have described its effect upon sick animals, especially upon horses, to which it was administered suc cessfully in an epidemic in which the note worthy symptoms were great emaciation and exhaustion.

Page: 1 2