466 EEPOBT— 1888. 



Vapour-densities of Aluminium Chloride. 



Nilson and Pettersson ' found for alnmininm chloride at temperatures 

 from 440° to 1260° vapour-densities varying from 7*789 to 4'277, the 

 density decreasing very rapidly from 440° to 760°, and still diminishing 

 regularly, till at about 1100° it remained nearly constant up to 1260°, 

 the value between these temperatures being somewhat lower than that 

 required by the formula AlCls on account of the platinum of the ap- 

 paratus being attacked by the chloride at these high temperatures. The 

 result of their observations showed that at no range of temperatures at 

 ■which the chloride was entirely gaseous was the formula Al2Clg appli- 

 cable. They adopt, therefore, AICI3 as the formula. 



Vapour- densities of Aluminium-ethyl and •methyl. 



L. Roux and E. Louise^ find, for aluminium-ethyl Cboiling at 195°-200°), 

 vapour- density SI at 235°, 6-2 at 258°, 2-5 at 310° and at 350°. The 

 first number corresponds to the formula A1.2(C2H5)5, and the last to less 

 than one-third of it. The authors conclude that the true formula is 

 Alo(C2H5)(-„ and that the diminution of density is due to some cause 

 unknown at present. 



Again, the same authors ^ find vapour-densities of aluminium- 

 methyl by V. Meyer's method, obtaining 5*1, 4*75, 4"6, 2-4, 1'8 for 

 densities at the temperatures 182°, 216°, 310°, 340°, 440° ; the theoreti- 

 cal density of the vapour for the formula Al2(CH3)5 is 5"02, which they 

 consider to be approximately reached at 310° ; as to the diminution of 

 vapour-density at higher temperatures, they find that that is due to a 

 decomposition of the compound into aluminium, olefines, and hydrogen. 



At the end of a paper on some vapour-densities by W. Griinewald and 

 V. Meyer,'' they say that Roux and Louise have given to aluminium- 

 ethyl the formula Al2(C2H5)g without, as seems to them, adequate proof ; 

 and that from investigations on aluminium-methyl they have come to 

 the conclusion that no molecule with the formula Al2(CH3)g exists at 

 any temperature. 



Va]}Our-densities of Stannous Chloride and Cuprous Chloride. 



Using a form of air-thermometer described by Goldschmidt and V. 

 Meyer, '^ Biltz and V. Meyer find the boiling-point of stannous chloride to 

 be 606"!.'' For this compound V. Meyer had, in conjunction with C. 

 Meyer, also with Ziiblin,^ found two molecular formulae Sn2Cl.i and 

 SnCl2 for different temperatures. Biltz and V. Meyer, on making a fresh 

 series of observations with very accurate determinations of the tempera- 

 tures at which they were made, found that there was no range of tem- 

 perature at which the vapour-density becomes constant, corresponding to 

 a molecular formula Sn2Cl4, but that the vapour-densities at 



temperatures 639° ; 678° ; 699° ; 759°-6 ; 790° ; 1113° 

 are . . 8-34; 8-57 ; 8'49 ; 8-26; 77; 7-08 



' Zeitschr. f. Phya. Chem. 8, p. 459 ; Ber. 20, 1887, Eef. 623. 



- C. R. 106, 73, 1888 ; Ber. Ref. 1888, p. 125. 



" C. R. 106, G02 ; Ber. 1888, Ref. 219. " Ber. 21, 1888, pp. 687 -701. 



* Ber. 15, 1882, j). 141. « Ber. 21, p. 22. 



' Ber. 12, 1879, p. 1195; and 13, 1880, p. 811. 



