Abstract: The relationship between the orientation of tetrahedral [SO₄]^2- in sulfate crystals such as barite,anhydrite, epsomite and jarosite and their morphology was studied from the standpoint of crystal chemistry,and the formation inechanisin of their morphology was analysed according to the structural orientation of tetrahedral [SO₄]^2- and the bonding energy between [SO₄]^2- and metal ions [M²⁺] during growth. It was found that the inorphology ofsulfates is related to the orientation of tetrahedral [SO₄]^2- in the crystal, i.e., the faces, the edges and faees of the tetrahedra normal to, are expected to grow slowly and observed in final form; in contrast, the faces, the vextices of the tetrahedra pointing to, usually grow fast, and will disappear.

Key words: sulfate crystals, anion coordinated polyhedra, bonding energy, morphology