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].

中文翻译：

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亚稳态单斜光卤石 KCl·MgCl2·6H2O 的结晶：光卤石家族中缺失的结构链接。

在天然和合成 K-Mg-Cl 盐水蒸发过程中，观察到形成几乎方形的板状钾光卤石晶体（氯化钾二氯化镁六水合物）。单晶结构分析揭示了单斜晶胞 [a = 9.251 (2)、b = 9.516 (2)、c = 13.217 (4) Å、β = 90.06 (2)° 和空间群 C2/c]。其结构与其他光卤石型化合物如NH4Cl·MgCl2·6H2O同晶。迄今为止，天然和合成光卤石 KCl·MgCl2·6H2O 仅以其斜方晶系形式 [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å 和空间群 Pnna] 为人所知。