222 



Prof. Roscoe on Vanadium, 



[Dec. 19, 



The following are the grounds upon which these conclusions are based ; 

 the experimental proofs are contained in the memoir : — 



(1) An oxide of vanadium exists having the atomic weight 6 7' 2 (that of 

 the metal of Berzelius). Hence vanadic acid contains more than 

 three atoms of oxygen, 



(2) The following vanadium oxides have been obtained, both in the dry 

 and wet way, and their composition determined : — 



(1) VO *, vanadium monoxidCj or vanadyl = 6 7' 2 



(2) YgOg, vanadium sesquioxide (Berzelius's suboxide) „ 150*4 

 . (3) YO^, vanadium dioxide 83*2 



(4) YaOg, vanadium pentoxide (vanadic acid) „ 182'4 



(3) The so-called terchloride of vanadium, VCl3(Y = 67'2), contains 

 oxygen; it is an oxychloride having the formula YOClg (Y=51'2) ; 

 it may be called vanadyl trichloride, or vanadium oxy trichloride, and 

 corresponds to POCI3, phosphoryl trichloride. 



(4) Three other solid oxychlorides exist, having the composition 



(1st) YOCl^, vanadyl dichloride, or vanadium oxydichloride. 

 (2nd) YOCl, vanadyl monochloride, or vanadium oxymonochloride. 

 (3rd) Y^O^Cl, divanadyl monochloride. 



(5) All the native vanadates are tribasic. 



(6) Vanadium pentoxide fused with sodium carbonate displaces three 

 molecules of carbon dioxide, showing that normal or ortho-sodium 

 vanadate is tribasic, the formula of this salt being NagYO^. 



(7) The so-called monovanadates are salts corresponding to the mono- 

 basic phosphates, and may be termed metavanadates ; thus, NaYOg, 

 NH^YOg, Ba2Y03. The so-called bivanadates are anhydro-salts, 

 similar in constitution to the anhydro-salts of chromic and boric 

 acids. 



(8) Yanadium nitride has been prepared, which, on analysis, was 

 shown to contain 51*2 parts by weight of vanadium to 14 parts of 

 nitrogen. 



All the reactions according to which vanadic acid was supposed (Berzelius, 

 Rammelsberg, Schafarik) to contain three atoms of oxygen with an atomic 

 weight Y=67'2, can equally well be explained when YgO. (Y = 51'2) is 

 taken to represent the composition of this substance. That this is the case 

 is seen from the following : — 



Berzelius's formula. New formulae. 



(V = 68-5. . = 8.) (V=51-2. 0-^16.) 



(1) Y03 + H,=Y0 +HA YA + 2H,=YA + 2 (H,0) 



(2) 3 (YO) + Cl;=Y03 + 2 (YCI3) 3 (YA) + 6Cl,=YA + 4 (YOClg) 



^ It is possible that the molecular formulae of these substances (VOjVOo), as well as 

 those of the solid oxychlorides, may be a multiple of the above. Further experiment 

 must decide whether or not these oxides, like the corresponding nitrogen compound?, 

 are an exception to the law of even atomicities. 



