Lanthanide tribromides solubilities

The triiodides are slightly more soluble in water than the tribromides [Table XXI (269-276)] the published value for samarium triiodide looks suspiciously high. The addition of hydrogen iodide produces a large decrease in the solubility of yttrium triiodide, from 66.98 wt % in water to 4.90 wt % in 63.45 wt % HI (in both cases at 0°C) (269). Other lanthanide triiodides behave similarly (272-274). 

Comparisons of solubilities of trichlorides, tribromides, and triiodides of the lanthanides in a variety of nonaqueous solvents can be found in a Russian review (310). Perhaps the widest range of solubilities of lanthanide(III) salts in nonaqueous media refers not to the trihalides but to the nitrates, whose solubilities in 31 solvents have been measured (312). Unfortunately, these measurements were carried out on the hexahydrates rather than anhydrous materials. 

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