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Crystal structure of the high‐ P polymorph of Ca 2 B 6 O 6 (OH) 10 ·2(H 2 O) (meyerhofferite)
Author(s) -
Comboni Davide,
Poreba Tomasz,
Pagliaro Francesco,
Battiston Tommaso,
Lotti Paolo,
Gatta Giacomo Diego,
Garbarino Gaston,
Hanfland Michael
Publication year - 2021
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520621009768
Subject(s) - crystallography , crystal structure , synchrotron , phase transition , boron , x ray crystallography , coordination number , diffraction , materials science , crystal (programming language) , chemistry , physics , ion , thermodynamics , organic chemistry , optics , programming language , computer science , nuclear physics
The crystal structure of the high‐pressure polymorph of meyerhofferite, ideally Ca 2 B 6 O 6 (OH) 10 ·2(H 2 O), has been determined by means of single‐crystal synchrotron X‐ray diffraction data. Meyerhofferite undergoes a first‐order isosymmetric phase transition to meyerhofferite‐II, bracketed between 3.15 and 3.75 GPa, with a large volume discontinuity. The phase transition is marked by an increase in the coordination number of the boron B1 site, from III to IV, leading to a more interconnected and less compressible structure. The main structural differences between the two polymorphs and the P ‐induced deformation mechanisms at the atomic scale are discussed.