SEPTEMBER, 1894.
VOL. XVI.
No. 9.
THE JOURNAL OF THE
AMERICAN CHEMICAL SOCIETY. AN ATTEMPT TO PREPARE MOLYBDENUM HEXACHLORIDE. BY
EDGARF. S M I T H A N D HENRYC. BURR. Received June 15, 1894.
I'
is well known that Teclu' obtained the hexachloride of tungsten by acting upon the trioxide of the metal with phosphorus pentachloride. T h e treatment of molybdenum trioxide in the same manner gave in one instance the compound MoCl,.POCI, and in another, MoCl,.PCl,. I n both of these derivatives the pentachloride of the metal is present. I t would, therefore, seem that the metal is incapable of carrying the sixth chlorine atom. Reute? heated both the trioxide of tungsten and that of molybdenum with silicon tetrachloride ; his products, however, were not hexachlorides. Passing by his observations it was thought that if a partially chlorinated molybdic acid were exposed to chlorinating agents the residual oxygen might be removed and that then perhaps the hexachloride would be present in the reaction product. To this end molybdenyl chloride, MoO,Cl,, was mixed with an equivalent quantity of phosphorus pentachloride and heated in a sealed tube in the presence of chlorine to a temperature of about 170' C. On cooling, it was found that the tube contained a mass of greenish-black crystals, which when carefully freed from adherent phosphorus oxychloride by distillation in a n atmosphere of chlorine gave a product that on analysis yielded figures approximating the pentachloride more closely than the hexachloride. Silicon tetrachloride was substituted for the phosphorus pentachloride and the experiment repeated. T h e resulting crystalline Chem., (Liebig's), 187, 255. Dissertation, Tubingen. 2893.
1 Ann.
9
578
E D G A R F . SMITH A N D JOS. G. HIRXS.
product was quickly removed to a boat and careful1~-distillet1 in a n atmosphere of carbon dioxide. Brown vapors ivtre expelled from the boat, which finall\. contained nothing but white si1ic:i. The brown vapors quickly condeiisetl i n the coltier portion of tlic tube, and upon anal>.siu ga1.e results var!.iiig ljet\veeii those required by the tetrachloride and peiitachloritle. T h e conclusion to be drawn from these experiments then is that notwithstanding the riiolybdeiiurii atom has already been partially chlorinated, and apparentlJ- is i n a suitable condition tu pass into the hexachloride, it yet does not do so, and i v e can hence only say that the molybdenum is either iiot srxivalent towards chlorine, or that at the elevated temperature at whicli these reactions took place, the hexncliloride, if formed, cannot exist, but is dissociated into lower chlorinated deriv a t’1ves. On heating pure, finely divided molybdenum, intimately inixed with sugar-carbon, i n an atmosphere of chlorine the invariable product was the pentachloride. The temperature doubtless exerts a great influence i n these reactions. I t has been obsenetl in this laboratory that when nietallic molybdenum acts upon an aqueous solution of ferric chloride rapid reduction of the ferric salt ensues with accompanying solution of the molybdenum. From a careful deterinination of the aniouiit of iron thus reduced, the niolybdenuni evidently dissolves as a hexad, and it may be that if such solutions were allowecl to evaporate slowly in desiccators, the hexachloride or some double salt, formed from it and ferrous chloride, might be lound. Search will be made in this direction. C X I V E R S I T Y OF P E N N S Y L T A S I A ,
June, 1694.
T H E ACTION OF HYDROCHLORIC ACID G A S UPON SODIUM VANADATE. BY EDGAK F. S M I T H A N D JOS. G . HInnS. R e c e i v e d l u n e 18.1894.
T
HE reaction of Debray’-the
volatilization of molybdic acid by means of hydrochloric acid gas,-has suggested a number of experiments which of late have been tried in various 1
Compf. vend., 46,
1 4 .
