SIR B. C. BEODIE ON TlIE CALCULUS OF CHEMICAL OPERATIONS. 



843 



Symbol of Tin. — In the decomposition of the gaseous chloride of tin into tin and 

 chlorine, the volume of chlorine formed is double the volume of the chloride decomposed. 

 Hence, putting y-^ as the number of units of stannic chloride decomposed, and oT'^'k'^. 

 «"%"'«?* as the symbols, respectively, of stannic chloride and of tin. 



and 



whence 



In all cases 



y^m= 2j/i +y,^n, 

 yim2=y2«2- 



m =2, n =0, 

 mi=4, «i=0, 



a minimum, and we hence have, as determined from the above equation, 



Symbol of tin /c^', 

 Symbol of bichloride of tin a^Ms 



and, assuming 130 as the density of bichloride of tin, 



2w{a)+iw{x)+y^,=l^0; 



y2w(*,)=59, 



whence 

 and 



W=3^i«;(«J=g59. 



Now, proceeding to construct the symbols of the other known gaseous compounds of 

 tin by processes precisely similar to those of which sufficient examples have already been 

 given in the case of the elements silicon and boron, and which it is unnecessjiry here to 

 repeat, we arrive at the following symbols : — 



SymboL 



Bichloride of tin . . . . 

 Chloride of stannic dimethyl 

 Chloride of stannic diethyl . 

 Bromide of stannic diethyl . 

 Iodide of stannic trimethyl . 

 Chloride of stannic triethyl 

 Bromide of stannic triethyl 

 Stannic dimethyl-diethyl 

 Stannic tetrethyl .... 



As in the corresponding cases which have already been discussed, there is but one 

 hypothesis which can be made as to the value of y.„ which is at once necessary and suf- 

 ficient, namely that ^2=1' which gives a'x^xy as the symbol of bichloride of tin. 





