Adsorption energy of stoichiometric molecules and surface energy at morphologically important facets of a Ca(OH)2 crystal

► The surface energy of Ca(OH)2 crystal is influenced by the size effect in the size range of ≤40 nm. ► The surface energy is 0.107 and 0.968 J m−2 for {0 0 0 1} and {1¯010} facets, respectively. ► The equilibrium morphology of a Ca(OH)2 crystal in vacuum is given by hexagonal-prism shape.