Calcium Hydroxide Chlorides: The Ternary System Ca(OH) 2 ‐CaCl 2 ‐H 2 O at 25, 40, and 60 °C, Phase Stoichiometry and Crystal Structure

The formation of calcium hydroxide chlorides is an important issue in processes of the chemical raw materials industry, in terms of purification of flue gases, and concrete/cement corrosion. Current information on phase compositions given in the literature are contradictory. In this work systematic solubility studies were carried out at 25, 40, and 60 °C in the system Ca(OH) 2 ‐CaCl 2 ‐H 2 O and the compositions of the ternary solid phases were precisely determined using the Schreinemakers' method. Two ternary phases were identified, the hydrate 3Ca(OH) 2 · CaCl 2 · 12H 2 O and the anhydrous calcium hydroxide chloride Ca(OH) 2 · CaCl 2 . The crystal structure of 3Ca(OH) 2 · CaCl 2 · 12H 2 O was solved by means of single‐crystal X‐ray diffraction at –123 °C (150 K).