OP ARTS AND SCIENCES. 43 



Potassic tetrabrompropionate, KCgHBr^O, . 2 HgO. By the action of 

 an aqueous solution of potassic carbonate on the acid a neutral solution 

 was obtained, from which by spontaneous evaporation the potassium salt 

 was deposited in the form of clustered needles. This salt is very solu- 

 ble in water and permanent in the air at ordinary temperatures, but 

 rapidly decomposed by heat. The air-dried salt gave up its water of 

 crystallization over sulphuric acid. 



I. 1,1571 grms. of the air-dried salt lost over HgSO^ 0.0882 grm. 



II.O. 

 II. 1.1304 grms. of the air-dried salt lost over HgSO^ 0.0858 grm. 

 H.O. 

 III. 1.0354 grms. of the anhydrous salt gave on ignition with HgSO^ 

 0.2165 grm. K^SO^. 



Calculated for KC3HBr402 . 2 HjO. Found. 



I. II. 



H^O 7.76 7.62 7.59 



Calculated for KCsHBr^O,. Found. 



K 9.14 9.39 



When heated in aqueous solution the barium salt was easily decom- 

 posed with the separation of an oil which distilled readily with steam. 

 Since tribromethylen was the only substituted hydrocarbon that could 

 be derived from tetrabrompropionic acid under these conditions, it was 

 converted directly into pent^bromethan. The salt was distilled with 

 an excess of baric hydrate, and the oily distillate absorbed by bromine 

 water. A solid residue was left after evaporation of the excess of 

 bromine, which melted at 53° when purified by crystallization from 

 alcohol, and on analysis gave the required percentage of bromine. 



0.0918 grm. of the substance gave 0.2041 grm. AgBr. 



Calculated for C^HBrg. Found. 



Br 94.12 94.61 



Carbonic dioxide was evolved in this decomposition, and the retort 

 residue contained baric bromide in large quantity. It may therefore 

 be expressed by the following equation : 



Ba(C3HBr,02)2 = 2 C^HBrg + BaBrg + 2 CO.. 



