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High-pressure synthesis of skiagite-majorite garnet and investigation of its crystal structureстатья
- Авторы: Ismailova L., Bobrov A., Bykov M., Bykova E., Cerantola V., Kantor I., Kupenko I., McCammon C., Dyadkin V., Chernyshov D., Pascarelli S., Chumakov A., Dubrovinskaia N., Dubrovinsky L.
- Журнал: American Mineralogist
- Том: 100
- Год издания: 2015
- Издательство: Mineralogical Society of America
- Местоположение издательства: United States
- DOI: 10.2138/am.2015.5278
- Аннотация: Iron garnet skiagite was synthesized in form of single crystals in a multi-anvil apparatus at pressure of 9.5 GPa and temperature of 1100 °C. Its structure (cubic, space group Ia3 ̅d, a=11.7511(2) Å, V=1622.69(5) Å3 , Dcalc=4.4931 g/cm3) was investigated using single crystal high-resolution synchrotron X-ray diffraction. Mössbauer spectroscopy revealed that Fe2+ and Fe3+ predominantly occupy dodecahedral (X) and octahedral (Y) sites, respectively, as expected for garnet structure. This was confirmed independently by nuclear forward scattering (NFS) data. The single-crystal X-ray diffraction suggests the structural formula of the studied skiagite-garnet to be Fe2+3(Fe2+0.234(2)Fe3+1.53(1)Si0.234(2))(SiO4)3, in agreement with the electron microprobe chemical analysis. It is supported by the X-ray absorption near-edge structure (XANES) spectra. The occurrence of Si and Fe2+ in the octahedral Y-site gives evidence that the synthetic garnet we studied is the solid solution of Fe-skiagite with the end-member Fe-majorite Fe2+3(Fe2+Si))(SiO4)3 with the amount of the latter of ~23 mol %.
- Добавил в систему: Бобров Андрей Викторович