The Polymorphic Nature of M3BiBr6 Halides (M=Cs, Rb) and their Reversible Intercalation with Water to Isomorphous Hydrates at Room Temperature

Chang JH, Wang Y, Doert T, Ruck M (2021)


Publication Type: Journal article

Publication year: 2021

Journal

Book Volume: 647

Pages Range: 478-484

Journal Issue: 5

DOI: 10.1002/zaac.202000402

Abstract

Bismuthates with composition M3BiBr6 (M=Rb, Cs) form series of polymorphs capable of reversible H2O incorporation at room temperature. The host compounds were synthesized by annealing mixtures of MBr/BiBr3, or by precipitation from acidic solution and removing water molecules from the host framework of the hydrates in a thermal dehydration reaction. While the compound oP-Rb3BiBr6 (space group Pbnm) is known from previous work, mP-Rb3BiBr6 crystallizes with a new type of structure (space group P21/c). For Cs3BiBr6, the oP-phase crystallizes isostructural to Cs3NdCl6 (space group Pbcm), the mC-phase isostructural to Cs3BiCl6 (space group C2/c) and the tP-phase isostructural to Tl3BiCl6 (space group P42/m). All crystal structures were refined from single crystal X-ray diffraction data. In both systems, the crystal structures of orthorhombic and the monoclinic phases are polytypes and differ by stacking sequence only. By intercalation of water molecules, all polytypes of M3BiBr6 transform to semi-hydrates M3BiBr6 ⋅ (Formula presented.) H2O. Both, the incorporation of water and the reverse process proceed without the host structure being changed. The inclusion of crystal water was also confirmed by IR-spectroscopy, thermal gravimetric analysis and mass spectrometry. The modification tP-Cs3BiBr6 features a crystal structure with higher density and does not accommodate water.

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How to cite

APA:

Chang, J.-H., Wang, Y., Doert, T., & Ruck, M. (2021). The Polymorphic Nature of M3BiBr6 Halides (M=Cs, Rb) and their Reversible Intercalation with Water to Isomorphous Hydrates at Room Temperature. Zeitschrift für Anorganische und Allgemeine Chemie, 647(5), 478-484. https://doi.org/10.1002/zaac.202000402

MLA:

Chang, Jen-Hui, et al. "The Polymorphic Nature of M3BiBr6 Halides (M=Cs, Rb) and their Reversible Intercalation with Water to Isomorphous Hydrates at Room Temperature." Zeitschrift für Anorganische und Allgemeine Chemie 647.5 (2021): 478-484.

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