Rubidium triiodide

Arsenic triiodide also dissolves, the saturated solution at 15° C. having density 3-661. Other soluble halides are potassium bromide, anhydrous ferric and aluminium chlorides 6 and tetramethyl ammonium iodide but the iodides of rubidium, cadmium, manganese and cobalt, also mercuric and stannic iodides, and cobalt and stannic bromides, are insoluble or only very slightly soluble in arsenic tribromide. The liquid also dissolves phosphoryl bromide and, very slightly, ammonium thiocyanate. In the mixed solutions of halides, the components may react chemically (cf. p. 106), but such is not always the case for example, with antimony tribromide a continuous series of solid solutions is formed.7... 

The cesium salt, which is considerably less solnble than the rubidium compound, can be prepared similarly, using 1.9g of cesium carbonate as the starting material. The bulk of the cesium triiodide crystallizes when the initial solution Is cooled in ice, and the mother liquor is worked np for... 

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