M. Liebig on the preparation of Iodide of Lithium, 29 



1*385, according to the proportion of the potash to the oxide 

 of bismuth, either red and yellow substances rich in oxygen are 

 obtained, or brown and black bodies poorer in oxygen. Boiled 

 with concentrated nitric acid, they leave a yellow residue of the 

 composition Bi0 4 + 2aq, difficultly soluble in this acid. 



Whatever the proportion of the potash to the bismuth, pro- 

 vided very concentrated potash was used, red bodies were 

 obtained, and never, as Arppe states, brown anhydrous bis- 

 muthic acid. 



The final product of decomposition of these red bodies by con- 

 centrated nitric acid is also Bi0 4 + 2Aq. 



Liebig has described* the following simple method of pre- 

 paring iodide of lithium and certain other iodides. One part of 

 amorphous phosphorus is placed in a mortar with forty times 

 its weight of warm water ; twenty parts of iodine are added, and 

 brought well in contact with the phosphorus by rubbing. The 

 liquid, at first dark brown, afterwards becomes colourless, and 

 more rapidly if heated in the water-bath. The liquid is poured 

 off from the small residue of phosphorus and quite saturated 

 with baryta, at first with carbonate, and afterwards with baryta- 

 water ; and then filtered from the phosphate and well washed out. 

 The clear filtrate now contains iodide of barium ; and by double 

 decomposition with carbonate of lithia iodide of lithium is 

 formed. The acid liquid formed by the action of iodine on 

 phosphorus and water, which consists of phosphoric and hydri- 

 odic acids, may be neutralized with lime instead of baryta ; the 

 method is otherwise the same. In the place of amorphous 

 phosphorus, ordinary phosphorus may be used; the action is 

 then quicker, but also more violent. 



Pettenkofer, under Liebig's direction, made experiments in 

 order to see if iodide of potassium could not be advantageously 

 prepared by the above method : one ounce of phosphorus was 

 treated with iodine in the manner described, as long as the 

 iodine dissolved without colouring the liquid; for this 13 \ 

 ounces of iodine were necessary. The clear liquid was poured 

 off from a small quantity of amorphous phosphorus which had 

 been formed, and milk of lime, prepared from 8 ounces of burnt 

 lime, added until the liquor was alkaline. After filtration, a hot 

 solution of 9 ounces of crystallized sulphate of potash in 48 

 ounces of water was added, and the whole allowed to stand six 

 hours. After filtration from the sulphate of lime, the clear 

 liquid was evaporated down to a quart, and a solution of pure 

 carbonate of potash added as long as a precipitate of carbonate 

 of lime was formed. This was filtered; and the clear liquid, when 



* Liebig's Annalen, February 1862. 



