802 CACODYL. 



This body is also a product of the decomposition of oxide of 

 cacodyl by sulphuretted hydrogen gas. It is an ethereal liquid, 

 of a highly disagreeable smell, which does not fume in air, is 

 heavier than water and insoluble in that liquid. The density of 

 its vapour is by experiment 7810? by calculation 8390, its com- 

 bining measure 2 volumes. It is resolved by hydrochloric acid, 

 into sulphuretted hydrogen and chloride of cacodyl. 



Persulphuret of cacodyl of the composition 2C 4 H 6 As-f 

 5S = 2 Kd + 5S, is formed when sulphur is dissolved in the 

 preceding compound or in cacodyl itself. It may be crystallized 

 from ether in colourless prisms, which fuse at 109.4 (43 cent.) 

 A protoseleniuret of cacodyl has also been formed. 



Chloride of cacodyl, C 4 H 6 As + Cl = Cd + Cl, is formed by 

 the digestion of oxide of cacodyl in hydrochloric acid, or by the 

 slow action of chlorine on cacodyl. It is a colourless ethereal 

 liquid, which does not fume in air, does not solidify at 49 

 ( 45 cent.), and is converted a little above 212 into a colour- 

 less vapour, which inflames in the air. Its odour is extremely 

 penetrating and stupifying. The density of its vapour is by 

 experiment 4560, by calculation 4860; its combining measure 

 2 volumes. Chloride of cacodyl combines with metallic chlo- 

 rides. 



Similar compounds of cacodyl with bromine, iodine, and 

 fluorine have been formed. 



Oxichloride of cacodyl, Kd O + 3 Kd Cl, is formed by treat- 

 ing the chloride with water, or by distilling it with hydrochlo- 

 ric acid. The density of its vapour i s by experiment 5460, 

 by calculation 5300 ; its combining measure 3 volumes. It is a 

 liquid very like the oxide, boiling at 22h.9<> (199 cent.) A 

 corresponding oxibromide of cacodyl and an oxyiudide of cac.odyl 

 have been formed. 



Cyanide of cacodyl, C 4 H 6 As -f-N C 2 = Kd Cy, is proofed 

 by the distillation of concentrated hydrocyanic acid or of a so- 

 lution of cyanide of mercury with oxide of cacodyl. It crystal- 

 lizes in fine prisms of a diamond lustre, highly limpid, which 

 emit a strong and insupportable odour. It is insoluble in water, 

 fusible at 9 1. 4 (33 cent.) and crystallizable by cooling. Its 

 density in the state of vapour is 4650 by experiment, and 4540 

 by calculation; its combining measure 2 volumes. The cyanide 

 is the most poisonous of the compounds of cacodyl. 



