The white and regular octahedral crystals of magnesium chloride hexammoniate are prepared by reaction crystallization between magnesium chloride and ammonia gas in ethylene glycol solution. The solubility of magnesium chloride hexammoniate in ethylene glycol solution saturated by ammonia gas has been determined by use of the ethylenediaminetetraacetic acid disodium salt (EDTA) titration method in the temperature range from (5 to 37.5) degrees C.