Pressure-induced Pb-Pb bonding and phase transition in Pb2SnO4

Dominik Spahr, Michał Stękiel, Dominik Zimmer, Lkhamsuren Bayarjargal, Katja Bunk, Wolfgang Morgenroth, Victor Milman, Keith Refson, Dominik Jochym, Peter J P Byrne, Björn Winkler

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High-pressure single-crystal to 20 GPa and powder diffraction measurements to 50 GPa, show that the structure of Pb2SnO4 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 6s2 lone electron pairs. On compression the lone electron pairs form bonds between Pb2+ ions. Also provided is an assignment of irreducible representations to the experimentally observed Raman bands.

Original languageEnglish
Pages (from-to)979-991
Number of pages13
JournalActa crystallographica Section B, Structural science, crystal engineering and materials
Issue numberPt 6
Publication statusPublished - 1 Dec 2020

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