Mechanism of pressure induced amorphization of SnI4: A combined x-ray diffraction-x-ray absorption spectroscopy study.
J Chem Phys
; 153(6): 064501, 2020 Aug 14.
Article
em En
| MEDLINE
| ID: mdl-35287441
ABSTRACT
We have studied the amorphization process of SnI4 up to 26.8 GPa with unprecedented experimental details by combining Sn and I K-edge x-ray absorption spectroscopy and powder x-ray diffraction. Standard and reverse Monte Carlo extended x-ray absorption fine structure (EXAFS) refinements confirm that the penta atomic SnI4 structural unit tetrahedron is a fundamental structural unit that appears preserved through the crystalline phase-I to crystalline phase-II transition that has been previously reported between 7 GPa and 10 GPa. Up to now, unexploited iodine EXAFS reveals to be extremely informative and confirms the progressive formation of iodine-iodine short bonds close to 2.85 Å. A coordination number increase of Sn in the crystalline phase-II region appears to be excluded, while the deformation of the tetrahedral units proceeds through a flattening that keeps the average I-Sn-I angle close to 109.5°. Moreover, we put in evidence the impact of pressure on the Sn near edge structure under competing geometrical and electronic effects.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2020
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Article