The Bureau of Mines investigated the effects of hcl concentration and solution temperature on the solubility and crystal form of the chlorides of CO, mn, and ni when sparged with hcl gas at temperatures of 20 deg., 40 Deg., and 60 deg. C. Increasing hcl concentration in solution caused the chlorides of CO, mn, and ni to crystallize (salt out) because of the common ion effect. The salting-out crystallization was most effective for nicl2, which had a solubility of 0.7 pct at 20 deg. C and maximum hcl concentration. Cocl2 salted out to a minimum solubility of 9.4 pct at 20 deg. C and 22 pct hcl concentration and increased in solubility at greater hcl concentrations because of the formation of chloride complexes. Mncl2 was intermediate in behavior. The effect of temperature on solubility was greatest for cocl2 and least for nicl2, 15 and 7 pct change, respectively, over the temperature range of 20 deg. to 60 deg. C. The salted-out chlorides of cobalt and nickel formed the hexahydrates and those of manganese formed the tetrahydrate in saturated metal chloride solutions at 20 deg. C and low concentrations of hcl. Increasing the temperature or the hcl concentration caused a loss in waters of hydration. At 60 deg. C, the salted-out crystals of nicl2 formed the tetrahydrate in hcl concentrations up to 18 pct and dihydrate at higher concentrations, while cobalt and manganese chlorides formed the dihydrates, even in water.