title: Absence of pressure-induced amorphization in LiKSO4.
abstract: Angle-resolved synchrotron radiation diffraction was used to investigate lithium potassium sulfate (LiKSO(4)) crystals under high pressure. We confirm that the title compound undergoes three phase transitions, α →β, β → γ and γ →δ, observed at around 0.8 GPa, 4.0 GPa and 7.0 GPa, respectively. Two competitive structures are proposed for the β-phase after powder diffraction data Rietveld refinements: an orthorhombic (space group Cmc 2(1)) or a monoclinic (space group Cc) structure. These structures correspond to the models of the low temperature phases. The γ-phase is indexed by a monoclinic structure. Finally, the δ-phase is found to be highly disordered. No evidence of any pressure-induced amorphous phase was observed up to 24 GPa, even under imposed highly non-hydrostatic conditions, contrary to previous propositions.
authors.affiliation: Laboratoire PMCN, CNRS, Université de Lyon 1, UMR 5586, F-69622 Villeurbanne Cedex, France. denis.machon@lpmcn.univ-lyon1.fr
authors.forename: D
authors.initials: D
authors.lastname: Machon
authors.forename: C B
authors.initials: CB
authors.lastname: Pinheiro
authors.forename: P
authors.initials: P
authors.lastname: Bouvier
authors.forename: V P
authors.initials: VP
authors.lastname: Dmitriev
authors.forename: W A
authors.initials: WA
authors.lastname: Crichton