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Pressure‐induced Pb–Pb bonding and phase transition in Pb 2 SnO 4
Author(s) -
Spahr Dominik,
Stękiel Michał,
Zimmer Dominik,
Bayarjargal Lkhamsuren,
Bunk Katja,
Morgenroth Wolfgang,
Milman Victor,
Refson Keith,
Jochym Dominik,
Byrne Peter J. P.,
Winkler Björn
Publication year - 2020
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/s205252062001238x
Subject(s) - lone pair , ambient pressure , raman spectroscopy , phase transition , crystallography , crystal structure , electrical resistivity and conductivity , diffraction , chemistry , condensed matter physics , materials science , phase (matter) , molecule , thermodynamics , physics , optics , organic chemistry , quantum mechanics
High‐pressure single‐crystal to 20 GPa and powder diffraction measurements to 50 GPa, show that the structure of Pb 2 SnO 4 strongly distorts on compression with an elongation of one axis. A structural phase transition occurs between 10 GPa and 12 GPa, with a change of space group from Pbam to Pnam . The resistivity decreases by more than six orders of magnitude when pressure is increased from ambient conditions to 50 GPa. This insulator‐to‐semiconductor transition is accompanied by a reversible appearance change from transparent to opaque. Density functional theory‐based calculations show that at ambient conditions the channels in the structure host the stereochemically‐active Pb 6 s 2 lone electron pairs. On compression the lone electron pairs form bonds between Pb 2+ ions. Also provided is an assignment of irreducible representations to the experimentally observed Raman bands.