JACKSON AND DERBY. — FERROUS IODIDE, 227 



preceded by the replacement of the iodine in the salt by bromine, and this 

 may account for the fact noted above, that an ethereal solution of bromine 

 does not act on amnionic iodide. 



Properties of Ammonic Bromiodobromide NH 4 BrIBr. 



The salt has a blood-red color in transmitted light, but is a brilliant 

 green with a metallic lustre by reflected light. The specimens examined 

 by us contained very elaborately twinned crystals with the branches at 

 right angles, but we are inclined to think that these consisted of ammonic 

 bromide, which is easily formed by the decomposition of our salt ; on 

 this account it smells of bromide of iodine, and on long standing leaves a 

 white residue of ammonic bromide ; the same decomposition takes place 

 to a limited extent when it is dissolved in ether ; the ethereal solution is 

 dark red. When treated with water, bromine and iodine are set free, 

 and a solution is formed. Hydrochloric acid sets free iodine. Sodic 

 hydrate or ammonic hydrate gives a black precipitate of iodide of nitro- 

 gen ; upon adding hydrochloric acid to the filtrate from this iodide of 

 nitrogen, bromine is set free. Sulphurous acid gives hydrobromic acid 

 and hydriodic acid. 



