Solubility Polytherms from 25 to 75 degrees C for Aqueous Systems of Lanthanum or Gadolinium Iodide with Potassium or Ammonium Iodide

Solubility in the (La,Gd)I(3)-(K,NH(4))I-H(2)O systems was studied by the isothermal method over the temperature range 25-75 degrees C. The solubility isotherms at 25, 50, and 75 degrees C have a eutonic character. Regions of crystallization were determined for LnI(3) center dot nH(2)O, where Ln = La or Gd and n = 3, 4, 6, or 9. Raising the concentration of a lanthanide iodide has a salting-out effect on potassium and ammonium iodides.