JACKSON AND BEHR. — SYMMETRICAL TRIIODBENZOL. 337 



always terminated by a single plane at an oblique angle to the sides of 

 the prism. It melts at 181°, and sublimes easily. It is freely soluble in 

 benzol, or carbonic disulphide even in the cold ; in chloroform it is 

 moderately soluble in the cold, freely soluble when hot ; in ether it is 

 moderately soluble, whether hot or cold ; in glacial acetic acid or ethyl 

 acetate it is somewhat soluble in the cold, freely soluble when hot ; in 

 alcohol or acetone it is slightly soluble in the cold, moderately soluble 

 when hot ; it is apparently insoluble in water, hot or cold. The best 

 solvent for it is alcohol. Strong hydrochloric acid has no apparent 

 action on it, even when hot ; strong nitric acid also has little or no 

 action on it, but fuming nitric acid acts on it in the way described in the 

 next paragraph. Strong sulphuric acid, when heated with it to its melt- 

 ing point, causes a partial decomposition, taking on a dark color ; at higher 

 temperatures the triiodbenzol sublimes out of the mixture. A strong 

 solution of sodic hvdrate seems to have no action on it, even when 

 boiling. 



An attempt was made to prepare triiodnitrobeuzol ; for this purpose 

 five grams of symmetrical triiodbenzol were boiled with 140 c.c. of a 

 mixture consisting of four parts of fuming nitric acid with one part of 

 common nitric acid. On cooling light yellow crystals appeared, and an 

 additional amount of the product was obtained by pouring the acid liquid 

 into about a litre of water, when a pale yellow flocculent precipitate was 

 formed, which was filtered out, after it had stood some time, and with 

 the crystals weighed 5.3 grams. This was purified by crystallization 

 from a mixture of four parts of alcohol with one of water, until it showed 

 the constant melting point 210°. This indicates that the substance is 

 triioddinitrobenzol, since Istrati and Georgescu * obtained a triioddini- 

 trobenzol melting at 210 o -212° from their triiodbenzol melting at 

 182°-184°. For still greater certainty the substance was dried at 100°, 

 and analyzed with the following result : — 



0.2049 gram of the substance gave by the method of Carius 0.2G44 

 gram of argentic iodide. 



Calculated for C B HI 3 (NO.,),. Found. 



Iodine 69.77 69.76 



The substance, therefore, is a dinitro compound, although obtained 

 from fuming nitric acid somewhat diluted with common nitric acid. We 



* Bui. Soc. Sci. Fiz., I. 66. 

 vol. xxxvi. — 22 



