M. Weber on Chloride of Iodine. 221 



red colour. On cooling, prismatic crystals are deposited, which 

 are very large if the cooling is slow. These, which are but 

 little soluble in the cold in bisulphide of carbon, contain almost 

 all the iodine. To obtain the chloride of carbon dissolved, the 

 liquid is agitated with water, which decomposes chloride of sul- 

 phur, and then with potass, over which the product is distilled; 

 this is pure chloride of carbon, C 2 CI 4 . 



Chlorine acting on solution of iodine produces chloride of 

 iodine, which is decomposed as fast as it is formed, so that the 

 iodine is constantly ready to take up fresh quantities of chlo- 

 rine. A small quantity of iodine can thus bring about the 

 decomposition of a large quantity of bisulphide of carbon by 

 chlorine. 



Terchloride of iodine (which dissolves in water) also acts upon 

 bisulphide in the presence of water; the same crystals are 

 formed ; to collect them the liquid is decanted, and the crystals 

 are dried in a current of dry chlorine. They are prisms, of an 

 orange yellow, greatly resembling acid potassic chromate; but 

 they are very deliquescent and produce a brown liquid, sc^that 

 their angle could not be determined. Water decomposes them, 

 with the separation of sulphur ; bisulphide also decomposes them. 

 Their composition is expressed by the formula IC1 3 + 2SC1 2 ; 

 when heated they lose a little iodine. 



Jaillard obtained a compound, by the action of chlorine on a 

 mixture of 1 part of iodine and 2 of sulphur, to which he 

 assigned the composition IC1 3 + SCI 2 ; Weber has prepared 

 and analyzed this body, and has found that it is identical with 

 the body described above. 



Sulphurous acid and sulphuretted hydrogen do not act on 

 each other if dry and at the ordinary temperature; in the 

 presence of water they produce water and deposit sulphur. 

 It is usually stated that the reaction is thus expressed, 

 2HS-f S0 2 =2HO + 3S; it is, however, more complex: pen- 

 tathionic acid is formed, which, in decomposing, liberates sul- 

 phur. The reaction has been investigated by De Luca and 

 Ubaldini*. The following method was used, to avoid as far as 

 possible the influence of heat on the deposited sulphur : — Two 

 normal solutions were prepared, one containing a weight of 

 \'7 gr. of sulphuretted hydrogen in 613*5 cub. centims. of water, 

 and the other 1*6 gr. of sulphurous acid in 54 cub. centims. of 

 water, these proportions corresponding to the above equation. 

 They were mixed in a stoppered bottle ; a milky deposit was 

 formed, from which the liquid became more or less clarified after 



* Comptes Rendus, June 10, 186/. 



