Ammonia uptake and release in the MnX2-NH3 (X = Cl, Br) systems and structure of the Mn(NH3)nX2 (n = 6, 2) ammines

Hazel Reardon, James M. Hanlon, Michael Grant, Imogen Fullbrook, Duncan H. Gregory

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Hexa-ammine complexes, Mn(NH3)6X2 (X = Cl, Br), have been synthesized by ammoniation of the corresponding transition metal halide and characterized by Powder X-ray diffraction (PXRD) and Raman spectroscopy. The hexa-ammine complexes are isostructural (Cubic, Fm-3m, Z = 4; a = 10.2742(6) Å and 10.527(1) Å for X = Cl, Br respectively). Temperature programmed desorption (TPD) demonstrated that ammonia release from Mn(NH3)6X2 complexes occurred in three stages corresponding to the release of 4, 1 and 1 NH3 equivalents respectively. The chloride and bromide both exhibit a deammoniation onset temperature below 323 K. The di-ammoniates from the first desorption step were isolated during TPD measurements and their crystal structures determined by Rietveld refinement against PXRD data (X = Cl: orthorhombic Cmmm, a = 8.1991(9) Å, b = 8.2498(7) Å, c = 3.8212(4) Å, Z = 2; X = Br: Orthorhombic Pbam, a = 6.0109(5) Å, b = 12.022(1) Å, c = 4.0230(2) Å, Z = 2).

Original languageEnglish
Pages (from-to)193-212
Number of pages20
JournalCrystals
Volume2
Issue number2
DOIs
Publication statusPublished - Apr 10 2012

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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