Crystallization of metastable monoclinic carnallite, KCl·MgCl2·6H2O: missing structural link in the carnallite family.

ABSTRACT: During evaporation of natural and synthetic K-Mg-Cl brines, the formation of almost square plate-like crystals of potassium carnallite (potassium chloride magnesium dichloride hexahydrate) was observed. A single-crystal structure analysis revealed a monoclinic cell [a = 9.251 (2), b = 9.516 (2), c = 13.217 (4) Å, β = 90.06 (2)° and space group C2/c]. The structure is isomorphous with other carnallite-type compounds, such as NH4Cl·MgCl2·6H2O. Until now, natural and synthetic carnallite, KCl·MgCl2·6H2O, was only known in its orthorhombic form [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å and space group Pnna].

SUBMITTER: Pannach M 

PROVIDER: S-EPMC7199198 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature