Titre du document / Document title

Morphology of crystals and conditions of phase stability in the K₂CrO₄-K₂Cr_zO₇ -H₂O system

Auteur(s) / Author(s)

KIRYANOVA E. V. ; ALEXANDROVA Yu. V. ; STARKOVA V. A. ;

Résumé / 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-K₂Cr₂O₇-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-K₂Cr₂O₇ (due to conformity of planes columns from diorthogroups in structure of both phases). Mutual adsorption effects of α-and 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.

Revue / Journal Title

Zapiski Vserossijskogo mineralogičeskogo obŝestva   ISSN 0869-6055 

Source / Source

2006, vol. 135, n^o1, pp. 103-111 [9 page(s) (article)]

Langue / Language

Russe

Editeur / Publisher

Nauka, Sankt-Peterburg, RUSSIE, FEDERATION DE  (1992) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 4673, 35400014675459.0080