text: Calcium hydroxide adopts a polymeric structure, as do all metal hydroxides.  The structure is identical to that of Mg(OH) (brucite structure); i.e., the cadmium iodide motif. Strong hydrogen bonds exist between the layers.
  Calcium hydroxide is produced commercially by treating (slaking) lime with water:
  :CaO + HO → Ca(OH)
  In the laboratory it can be prepared by mixing aqueous solutions of calcium chloride and sodium hydroxide. The mineral form, portlandite, is relatively rare but can be found in some volcanic, plutonic, and metamorphic rocks. It has also been known to arise in burning coal dumps.
  The positively charged ionized species CaOH has been detected in the atmosphere of S-type stars.