one of the Trivalent Group of Elements. 313 



The atomic weight of vanadium was determined (1) by reducing 

 the pentoxide to trioxide in a current of hydrogen, (2) by the ana- 

 lysis of the oxytrichloride. The atomic weight obtained as the mean 

 of a large number of well-agreeing experiments is 51*3. 



The metal itself has not yet been obtained ; but a compound of 

 vanadium and nitrogen has been prepared, shown by direct analysis 

 to contain 14 parts by weight of nitrogen to 51*3 parts by weight of 

 vanadium, corresponding to the formula VN. The existence of this 

 compound is proof positive of the true atomic weight of the metal ; 

 and the nitride serves as the point of departure from which to seek 

 for the metal and the true chlorides of vanadium, one of which, VC1 3 , 

 has already been prepared by the action of chlorine upon the nitride. 

 It is a dark-brown liquid, which decomposes when thrown into water, 

 forming a green solution containing V 2 O 3 . The speaker demon- 

 strated the fact that the oxychloride, V O CI 3 , when thrown into 

 water decomposes with formation of a yellow solution of vanadium 

 pentoxide, V 2 O 5 ; whilst the trichloride, V CI 3 , on being similarly 

 treated, yields a green solution containing the metal in solution as 

 trioxide, V 2 O 3 . He then compared these reactions with the decom- 

 position of the corresponding phosphorus compounds, P O CI 3 and 

 P CI 3 , forming P 2 O 3 and P 2 O 3 , and rendered these reactions visible 

 by obtaining a precipitate of yellow silver phosphate in the first case, 

 and of black metallic silver in the second. 



The characters of the vanadates themseves bear out the analogy 

 of the highest oxide with the corresponding oxides of phosphorus 

 and arsenic. In the first place, all the naturally occurring vanadates 

 are tribasic ; secondly, the true character of vanadic acid is shown to 

 be tribasic by the fact that, when the pentoxide is fused with sodium 

 carbonate, three atoms of CO 2 are liberated, and the normal or ortho- 

 vanadate, Na 3 V 2 s (corresponding to Na 3 P 2 O 8 ), is formed; thirdly, 

 the so-called monovanadates are monobasic salts, corresponding to 

 the monobasic phosphates, and may be termed metavanadates, thus, 

 Na VO 3 and Ba2V0 3 , whilst the so-called bivanadates are anhydro- 

 salts. 



All the reactions by which Berzelius explained the facts he dis- 

 covered can equally well be represented according to the new atomic 

 weight and constitution, thus : — 



Berzelius 's Formula. 



V = 68-5. = 8. 



(1) V0 3 4-H 2 =V04-H 2 2 . 



(2) 3(V0) + C1 6 =V0 3 +2(VC1 3 ). 



New Formulas. 

 V=51-3. = 16. 

 V 2 5 + 2H 2 =V 2 3 + 2(H 2 0), 



3(V 2 3 ) + 6C1 2 =V 2 5 + 4(VO CI 3 ). 



