6533b828fe1ef96bd1287798

RESEARCH PRODUCT

Comment on “High-pressure x-ray diffraction study of YBO3/Eu3+, GdBO3, and EuBO3: Pressure-induced amorphization in GdBO3” [J. Appl. Phys. 115, 043507 (2014)]

Alfonso MunozDaniel ErrandoneaJavier González-platasJavier González-platas

subject

DiffractionBulk modulusEquation of stateAb initio quantum chemistry methodsComputational chemistryChemistryX-ray crystallographyCompressibilityGeneral Physics and AstronomyThermodynamicsElastic modulusModuli

description

High-pressure x-ray diffraction studies on vaterite-type borates were reported on the above paper and their room-temperature P-V equation of state (EOS) determined. YBO3/Eu3+ and GdBO3 were found to have bulk moduli around 320 GPa, 90% larger than the bulk modulus obtained for EuBO3. Consequently, it was stated that vaterite-type borates are as incompressible as cubic BN. Such a different compressional behavior of isomorphic borates contradicts the known systematic of related borates. Here, we show that the conclusions reported on the above article could be hindered by experimental errors and artifacts. Ab initio calculations support our criticism giving similar bulk moduli (130–141 GPa) in the three compounds. Based upon these arguments, we conclude that the high-pressure behavior of vaterite-type borates should be revised using accurate experimental techniques. Finally, a methodological critic on EOS fits and to structural refinements is also presented.

https://doi.org/10.1063/1.4881057