Abstract
LONDON
Chemical Society, Aptil 21.-Prof. Williamson, F.R.S., president, in the chair. T. Patchett was elected a Fellow. Prof. Roscoe, F.R. S., delivered a lecture on “Vanadium.” This metal was discovered in 1830 by Sefstrôm, who also ascertained some of the most peculiar characters of the substance, and prepared some of its compounds in the pure state. Sefstrom not having leisure to prosecute the full examination of the new metal, handed over his preparations to Berzeliiis; and it is to the investigations of the great Swede that we owe almost all our acquaintance with the chemistry of vanadium. He found the atomic weight of the metal = 68*5, and wrote its oxides:-VO, V02, VO:J, and its chloride VCÄ13. Some years afterwards Rammelsberg observed that the mineral vanadinite, a double salt of lead vanadate and lead chloride, is isomorphous, with apatite and with mimetesite, the former containing phosphoric, the latter arsenic acid. This crystallographic analogy would have led to the conclusion that the oxide of vanadium in the vanadinite has the formula V205, agreeing with the corresponding oxides of phosphorus and arsenic, P205, and As205. But the unyielding facts Berzeliiis had obtained in his analysis, and according to which the oxide in question was represented by the formula VOa, compelled to regard vanadinite as an exception to the law of isomorphism. Prof. Roscoe, having come into the possession of a plentiful source of vanadium, determined to ascertain whether there really was such an exception, or whether Berzelius's formula may not perhaps be erroneous. He soon found the latter to be the case. He proved that the substance supposed by Berzeliiis to be vanadium, is not the metal, but an oxide, and that the true atomic weight of the metal is 51*3. Thus the V03 of Berzelius becomes V2Og, corresponding to P205 and As205. The lecturer went on to demonstrate that the characters of the vanadates bear out the analogy of V205, with and As2Og, and vanadium, hitherto standing in no definite relation to other elements, must therefore be regarded as a member of the well-known Triad class of elementary substances, comprising nitrogen, phosphorus, boron, arsenic, antimony, and bismuth. The above-mentioned source of vanadium is a by-product obtained in the preparation of cobalt from the copper-bearing beds of the lower Keuper sandstone of the Trias at Alderley Edge, in Cheshire.
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Societies and Academies . Nature 1, 662–666 (1870). https://doi.org/10.1038/001662a0
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DOI: https://doi.org/10.1038/001662a0