Pressure-Induced Collapse Transition in BaTi2Pn2O (Pn = As, Sb) with an Unusual Pn-Pn Bond Elongation.
Inorg Chem
; 60(4): 2228-2233, 2021 Feb 15.
Article
en En
| MEDLINE
| ID: mdl-33502187
ABSTRACT
Making and breaking bonds in a solid-state compound greatly influences physical properties. A well-known playground for such bonding manipulation is the ThCr2Si2-type structure AT2X2, allowing a collapse transition where a X-X dimer forms by a chemical substitution or external stimuli. Here, we report a pressure-induced collapse transition in the structurally related BaTi2Pn2O (Pn = As, Sb) at a transition pressure Pc of â¼15 GPa. The Pn-Pn bond formation is related with Pn-p band filling, which is controlled by charge transfer from the Ti-3d band. At Pc, the Sb-Sb distance in BaTi2Sb2O shrinks due to bond formation, but interestingly, the Sb-Sb expands with increasing pressure above Pc. This expansion, which was not reported in ThCr2Si2-type compounds, may arise from heteroleptic coordination geometry around titanium, where a compression of the Ti-O bond plays a role. Electrical resistivity measurements of BaTi2Sb2O up to 55 GPa revealed an increasing trend of the superconducting transition temperature with pressure. This study presents structure motifs that allow flexible bonding manipulation and property control with heteroleptic coordination geometry.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Inorg Chem
Año:
2021
Tipo del documento:
Article
País de afiliación:
Japón