The 108 dissymmetric phases were obtained as a result of X anions ordering in elpasolite structure A2BB ′ X6 (ordered perovskite) using group theoretical methods. The critical order parameters which transform according to the irreducible representations of Γ and X points of Brillouin zone of O 5 h -F m3m space group were considered only. Polyhedral structures showed for dissymmetric phases which are accompanied by appearing of ferroelectricity at phase transition. All results are summarized in convenient tables.