On the synthesis and structure of the copper-molybdenum oxide bronzes: Monoclinic Cu2Mo10O30 and orthorhombic CuMo9O26

M. Ørndrup Nielsen, P. Brilner Lund, V. McKee, D. B. Ravnsbæk, T. E. Warner*, C. Wegeberg

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Cu2Mo10O30 was prepared as a monophasic material comprising dark blue platy crystals by reacting Cu with MoO3 under argon at 550 ​°C. Single-crystal X-ray diffractometry showed that Cu2Mo10O30 is a stoichiometric compound that crystallizes with a monoclinic (C2/c) cell: a ​= ​16.6359(6); b ​= ​9.3112(3); c ​= ​27.1597(9) Å; β ​= ​102.621(3)° (Z ​= ​8). Electron paramagnetic resonance spectroscopy revealed that Cu2Mo10O30 displays mixed-valency; (CuI 2−xCuII x)(MoV 2+xMoVI 8−x)O30 (0 ​≪ ​x ​≤ ​2). Differential scanning calorimetry and in situ high-temperature powder X-ray diffractometry showed that Cu2Mo10O30 decomposes ≳550 ​°C under an inert atmosphere. Dark blue acicular crystals of CuMo9O26 were discovered as a side-product in materials prepared inside evacuated glass ampoules at 500 ​°C. Single-crystal X-ray diffractometry showed these to crystallize with an orthorhombic (Pmmn) cell: a ​= ​3.74190(10); b ​= ​26.4941(4); c ​= ​9.15300(10) Å; (Z ​= ​2). Rietveld refinement of the powder X-ray diffraction data for these materials revealed Cu2Mo10O30 with minor CuMo9O26 and ‘Cu0.1MoO3’.

Original languageEnglish
Article number121259
JournalJournal of Solid State Chemistry
Volume285
Number of pages8
ISSN0022-4596
DOIs
Publication statusPublished - May 2020

Keywords

  • Chemical synthesis
  • Crystal structure
  • Differential scanning calorimetry (DSC)
  • Electron paramagnetic resonance spectroscopy
  • Oxides
  • X-ray diffraction

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