1878.] Chlor-iodide and Brom-iodide of Ethylidene. 425 



prepared by passing washed chlorine into 4 oz. of water, holding 400 

 grains of iodine in suspension, till almost all the iodine was dissolved. 

 The vessel containing the iodine must be surrounded with cold water, 

 and repeatedly shaken during the passage of the gas. 



This method is quite analogous to that by which I obtained its 

 isomer, the chlorio-dide of ethylene.* 



Second Process. — One molecule of iodide of aluminium (A] 2 T 6 ) was 

 dissolved in three times its weight of dry carbon disulphide, and 

 added drop by drop without exposure to air to six molecules of chlo- 

 ride of ethylidene (C 3 H 4 C1 2 ) diluted with an equal volume of the disul- 

 phide. The chloride of ethylidene must be surrounded with ice, and 

 kept in a state of continual agitation during the addition of the 

 aluminium iodide solution. By mixing the reacting bodies in this 

 way, the chloride is always in excess, and only one atom of chlorine in 

 each molecule is supplanted by one of iodine. After the addition of 

 the aluminium iodide, the product was filtered through asbestos, 

 washed with water, and heated in a water-bath to drive off the carbon 

 disulphide. f The residue, which had been previously washed with 

 dilute potash, on being heated above 100°, commenced to distil at 

 110°, and between that temperature and 15.5° C. about two-thirds of 

 it passed over. (The liquid distilling above 155° was iodide of 

 ethylidene). This yielded, on fractioning, a large quantity of an oil 

 boiling at the same temperature, and having the same properties as 

 that prepared by the first process. On submitting this body to 

 analysis I obtained the following numbers : 



Theory C 2 H 4 C1I. Experiment. 



Carbon.....^. 12*60 12 92 



Hydrogen....:': 2*10 .. 2 -23 



Chlor-iodide of ethylidene has a sweet taste, and is almost colour- 

 less when freshly prepared. Its specific gravity at 19° C. is = 2*054. 

 It distils without decomposition between 117 and 119° C. It will be 

 observed that its boiling point is 20 degrees lower than that of its 

 isomer, the chlor-iodide of ethylene (137° C), and is intermediate 

 between those of the iodide (177° C.) and chloride of ethylidene 

 (58° C). 



Of these processes, the second is easier of execution and yields a 

 larger product. 



CH 3 



Brom-iodide of ethylidene | . This body I obtained also from 



CHBrI 



the iodide of ethylidene, and by a process almost identical with the 

 * Proc. Roy. Soc, xi, 590. 



t It is advisable to use Wiirtz's tube with two bulbs in distilling the carbon di- 

 sulphide, as a large quantity of the chlor-iodide passes over with the disulphide 

 when the distillation is conducted in the usual way. 



VOL. XXVII. 2 P 



