ФОРМА КРИСТАЛЛОВ И УСЛОВИЯ СТАБИЛЬНОСТИ ФАЗ В СИСТЕМЕ К2СRО4-К2СR2О7-Н2О

Abstract

For crystals with the structurally related radicals [XO4]2- and [X2O7]2- - tarapacaite (β-K2CrO4), lopezite (α-K2Cr2O7), and the phase β-K2Cr2O7, the regularities of their morphogenesis were studied during their combined crystallization within system K2CrO4-К2Сr2O7-H2O. Change of elongation of lopezite crystals from [001] parallel in the binary solutions to the [100] parallel one, in sybeutonic solutions, in the range near 28 °C isotherm is resulting from the specific adsorption of metastable phase β-K2Cr2O7 on {010} faces of α-K2Cr207 (due to conformity of planes columns from diorthogroups in structure of both phases). Mutual adsorption effects of αand β-K2Cr2O7 phases is the cause of hypomorphy of their crystals. Increase in development of {001} faces on tarapacaite in subeutonic solutions is connected with partial dimerization of orthogroups in the [001] direction. The field of stable growth of the β-K2Cr2O7 phase from water solutions was localized for the first time, so as the detail study of edging of its crystals.