New Quaternary Alkali-Metal Hypodiphosphate Hydrates: Preparation, Crystal Structure, Vibrational Spectrum, and Thermal Behavior of K4P2O6·8H2O and Na2K2P2O6·8H2O in Comparison to Na4P2O6·10H2O

Authors

  • PD Dr. Mimoza Gjikaj,

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    1. Institut für Anorganische und Analytische Chemie der Technischen Universität Clausthal, Paul-Ernst-Strasse 4, 38678 Clausthal-Zellerfeld, Germany
    • Institut für Anorganische und Analytische Chemie der Technischen Universität Clausthal, Paul-Ernst-Strasse 4, 38678 Clausthal-Zellerfeld, Germany, Fax: +49-5323-722995
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  • Peng Wu,

    1. Institut für Anorganische und Analytische Chemie der Technischen Universität Clausthal, Paul-Ernst-Strasse 4, 38678 Clausthal-Zellerfeld, Germany
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  • Wolfgang Brockner

    1. Institut für Anorganische und Analytische Chemie der Technischen Universität Clausthal, Paul-Ernst-Strasse 4, 38678 Clausthal-Zellerfeld, Germany
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  • Dedicated to Professor Rudolf Hoppe on the Occasion of His 90th Birthday

  • Supporting Information for this article is available on the WWW under http://dx.doi.org/10.1002/zaac.201200130 or from the author.

Abstract

Single crystals of the alkali-metal hypodiphosphates K4P2O6·8H2O (1) and Na2K2P2O6·8H2O (2) could be obtained and their crystal structures determined. The compounds 1 and 2 crystallize isotypic in the orthorhombic space group Pbca (no. 61) with four formula units in the unit cell. The crystal structures are built up by discrete [P2O6]4– units in an ethane-like staggered conformation, by the corresponding alkali-metal cations and water molecules. FT-IR/FIR and FT-Raman spectra of the crystalline title compounds were recorded and a complete assignment for the [P2O6]4– modes is proposed. Raman spectra of aqueous hypodiphosphate solutions deliver additional polarization data supporting the band assignment. Compounds 1 and 2 show a complete H2O loss in case of slow heating avoiding the formation of a hydrate melt.

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