TY - JOUR
T1 - Redetermination of metarossite, CaV5+ 2O6·2H2O
AU - Kobsch, Anaïs
AU - Downs, Robert T.
AU - Domanik, Kenneth J.
N1 - Funding Information:
This project was the work of summer intern AK, and she thanks the Downs lab at the University of Arizona, the Ecole Normale Superieure de Lyon and the Universite Claude Bernard Lyon 1 for the opportunity. Funding was provided by the Ecole Normale Superieure de Lyon and the region Auvergne-Rhone-Alpes (France), through the grant Explo'ra Sup
Publisher Copyright:
© Wang et al. 2016.
PY - 2016
Y1 - 2016
N2 - The crystal structure of metarossite, ideally CaV2O6·2H2O [chemical name: calcium divanadium(V) hexaoxide dihydrate], was first determined using precession photographs, with fixed isotropic displacement parameters and without locating the positions of the H atoms, leading to a reliability factor R = 0.11 [Kelsey & Barnes (1960). Can. Mineral. 6, 448-466]. This communication reports a structure redetermination of this mineral on the basis of single-crystal X-ray diffraction data of a natural sample from the Blue Cap mine, San Juan County, Utah, USA (R1 = 0.036). Our study not only confirms the structural topology reported in the previous study, but also makes possible the refinement of all non-H atoms with anisotropic displacement parameters and all H atoms located. The metarossite structure is characterized by chains of edge-sharing [CaO8] polyhedra parallel to [100] that are themselves connected by chains of alternating [VO5] trigonal bipyramids parallel to [010]. The two H2O molecules are bonded to Ca. Analysis of the displacement parameters show that the [VO5] chains librate around [010]. In addition, we measured the Raman spectrum of metarossite and compared it with IR and Raman data previously reported. Moreover, heating of metarossite led to a loss of water, which results in a transformation to the brannerite-type structure, CaV2O6, implying a possible dehydration pathway for the compounds M 2+V2O6·xH2O, with M = Cu, Cd, Mg or Mn, and x = 2 or 4.
AB - The crystal structure of metarossite, ideally CaV2O6·2H2O [chemical name: calcium divanadium(V) hexaoxide dihydrate], was first determined using precession photographs, with fixed isotropic displacement parameters and without locating the positions of the H atoms, leading to a reliability factor R = 0.11 [Kelsey & Barnes (1960). Can. Mineral. 6, 448-466]. This communication reports a structure redetermination of this mineral on the basis of single-crystal X-ray diffraction data of a natural sample from the Blue Cap mine, San Juan County, Utah, USA (R1 = 0.036). Our study not only confirms the structural topology reported in the previous study, but also makes possible the refinement of all non-H atoms with anisotropic displacement parameters and all H atoms located. The metarossite structure is characterized by chains of edge-sharing [CaO8] polyhedra parallel to [100] that are themselves connected by chains of alternating [VO5] trigonal bipyramids parallel to [010]. The two H2O molecules are bonded to Ca. Analysis of the displacement parameters show that the [VO5] chains librate around [010]. In addition, we measured the Raman spectrum of metarossite and compared it with IR and Raman data previously reported. Moreover, heating of metarossite led to a loss of water, which results in a transformation to the brannerite-type structure, CaV2O6, implying a possible dehydration pathway for the compounds M 2+V2O6·xH2O, with M = Cu, Cd, Mg or Mn, and x = 2 or 4.
KW - brannerite
KW - crystal structure
KW - hydrogen bonds
KW - metarossite
KW - phase transformation
KW - redetermination
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U2 - 10.1107/S2056989016012433
DO - 10.1107/S2056989016012433
M3 - Article
AN - SCOPUS:84999089866
VL - 72
SP - 1280
EP - 1284
JO - Acta Crystallographica Section E: Crystallographic Communications
JF - Acta Crystallographica Section E: Crystallographic Communications
SN - 2056-9890
ER -