The crystal structure of manganilvaite, CaFe2+Fe3+ (Mn2+,Fe2+)(Si2O7)O(OH), from the Ossikovo Pb-Zn skarn deposit, Rhodope Mountains, Bulgaria, was refined in space group P21/a, with a 13.0250(7), b 8.8514(5), c 5.8486(3) Å, β 90.167(1)°, V 674.28(7) Å3, Z = 4, using combined neutron and X-ray powder diffraction as well as single-crystal X-ray-diffraction data. The empirical chemical formula proposed on the basis of the Rietveld refinements is: (Ca0.9Mn0.12+) (Fe0.832+Fe0.173+) (Fe0.172+Fe0.833+) (Mn0.512+Fe0.492+) (Si2O7)O(OH). The occupancy of the M11 site (0.83Fe2+ + 0.17Fe3+) corresponds to an order parameter Q of 0.65(10). The high Mn content leads to strong enhancement (14%) of Fe2+ → Fe3+ charge transfer in comparison to Mn-free ilvaite from Seriphos, Greece, as observed by Mössbauer spectroscopy.
- Combined X-ray and neutron powder diffraction
- Mössbauer spectroscopy
- Ossikovo mine
- Rietveld refinement
- Single-crystal X-ray diffraction
ASJC Scopus subject areas
- Geochemistry and Petrology