688 



insoluble in water, are produced, but witb sulphuric acid it forms 

 fine, colourless crystals, which by analysis gave the formula 



Sn 2 C 12 H 15 S0 4 orSn 2 (C 4 H 5 ) 3 S0 4 . 



For this compound I propose the name of sulphate of distannic 

 triethyl. It has, in a remarkable degree, the unusual property of 

 being more soluble in cold than in hot water. A cold saturated 

 solution becomes semi-solid by raising the temperature somewhat 

 below ebullition. 



A consideration of the elements of the above formula furnished 

 an idea of these bodies being either double salts, compounded of 

 one equivalent of stannic diethyl with one equivalent of any salt, 

 Sn C 4 H 5 X, or else a combination of three equivalents of stannic di- 

 ethyl, with one equivalent of an inorganic salt Sn X 2 , resulting in two 

 molecules of the sesqui-ethylated salt. Thus 



3 Sn (C 4 H 5 ) 2 + Sn C1 2 =2 Sn 2 (C 4 H 5 ) 3 Cl. 



Experiment proves that the former bodies mix, but do not combine 

 chemically, at any moderate heat. The latter bodies, on the other 

 hand, exhibit strong chemical action, and disengage great heat during 

 combination. 



Bichloride of tin forms an oily body with stannic diethyl, chiefly 

 composed of chloride of distannic triethyl, which by treatment with 

 potash may be made to furnish the corresponding salts without 

 difficulty. 



Iodide of distannic triethyl may often be found amongst the pro- 

 ducts of the action of tin on iodide of ethyl. It is very probably 

 identical with the oil noticed by Riche and Cahours, and described 

 by them as possessing the pungent odour of oil of mustard. 



These salts also must be considered to be identical with those 

 described by Lowig under the somewhat inappropriate name of 

 " methyl o-stanethyls." The present name is suggested as more in 

 accordance with their true constitution. They finally pass, by the 

 action of zincethyl, into the radical stannic diethyl. 



The presence of iodide of distannic triethyl amongst the stannic 

 bodies in Lowig' s experiments can be satisfactorily accounted for, by 

 presuming the incomplete reduction of the iodides by the alloy of 

 tin and sodium, employed in the reactions. 



The behaviour of zincethyl towards the chlorides of tin may be 



