%0 Journal Article %1 WOS:000356566100034 %A Maczka, Miroslaw %A Szymborska-Malek, Katarzyna %A de Pinheiro, Gardenia Sousa %A Freire, Paulo Tarso Cavalcante %A Majchrowski, Andrzej %C 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA %D 2015 %I ACADEMIC PRESS INC ELSEVIER SCIENCE %J JOURNAL OF SOLID STATE CHEMISTRY %K High Phase Raman pressure; scattering} transition; {Borate; %P 239-244 %R 10.1016/j.jssc.2015.05.002 %T Pressure-induced phase transitions in acentric BaHf(BO3)(2) %V 228 %X High-pressure Raman scattering studies revealed that BaHf(BO3)(2) is more compressible than calcite-type orthoborates and calcite, aragonite or dolomite carbonates. It undergoes a first-order reversible pressure-induced phase transition in the 3.9-4.4 GPa pressure range. Second structural change is observed at 9.2 GPa. The intermediate phase is most likely trigonal. However, Raman results suggest increase in the number of distinct BO3 groups from two in the ambient pressure phase to at least three in the intermediate phase. This intermediate phase is also strongly compressible and strong pressure dependence of the lattice modes proves that the main changes under pressure occur within the layers built from BaO6 and HfO6 octahedra. The second phase transition leads most likely to lowering of the trigonal symmetry, as evidenced by significant increase of the number of observed bands. The pressure coefficients of the Raman bands of the high-pressure phase are relatively small, suggesting more dense arrangement of the metal-oxygen polyhedra and BO3 groups in this phase. It is worth noting that the high-pressure phase was not reached in the second compression experiment up to 10 GPa. This behavior can be most likely attributed to worse hydrostatic conditions of the first experiment. (C) 2015 Elsevier Inc. All rights reserved.

@article{WOS:000356566100034, abstract = {High-pressure Raman scattering studies revealed that BaHf(BO3)(2) is more compressible than calcite-type orthoborates and calcite, aragonite or dolomite carbonates. It undergoes a first-order reversible pressure-induced phase transition in the 3.9-4.4 GPa pressure range. Second structural change is observed at 9.2 GPa. The intermediate phase is most likely trigonal. However, Raman results suggest increase in the number of distinct BO3 groups from two in the ambient pressure phase to at least three in the intermediate phase. This intermediate phase is also strongly compressible and strong pressure dependence of the lattice modes proves that the main changes under pressure occur within the layers built from BaO6 and HfO6 octahedra. The second phase transition leads most likely to lowering of the trigonal symmetry, as evidenced by significant increase of the number of observed bands. The pressure coefficients of the Raman bands of the high-pressure phase are relatively small, suggesting more dense arrangement of the metal-oxygen polyhedra and BO3 groups in this phase. It is worth noting that the high-pressure phase was not reached in the second compression experiment up to 10 GPa. This behavior can be most likely attributed to worse hydrostatic conditions of the first experiment. (C) 2015 Elsevier Inc. All rights reserved.}, added-at = {2022-05-23T20:00:14.000+0200}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, author = {Maczka, Miroslaw and Szymborska-Malek, Katarzyna and de Pinheiro, Gardenia Sousa and Freire, Paulo Tarso Cavalcante and Majchrowski, Andrzej}, biburl = {https://www.bibsonomy.org/bibtex/2135f1cf5f70de69cb9ea4253543fd0cd/ppgfis_ufc_br}, doi = {10.1016/j.jssc.2015.05.002}, interhash = {e7b9033db931b9f82bb7cef65cd9bd17}, intrahash = {135f1cf5f70de69cb9ea4253543fd0cd}, issn = {0022-4596}, journal = {JOURNAL OF SOLID STATE CHEMISTRY}, keywords = {High Phase Raman pressure; scattering} transition; {Borate;}, pages = {239-244}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, pubstate = {published}, timestamp = {2022-05-23T20:00:14.000+0200}, title = {Pressure-induced phase transitions in acentric BaHf(BO3)(2)}, tppubtype = {article}, volume = 228, year = 2015 }