title: Structures and phase transitions of trigonal ZrMo2O8 and HfMo2O8.
abstract: This paper describes the structures, thermal-expansion properties and phase transitions of the trigonal forms of ZrMo(2)O(8) and HfMo(2)O(8). Both phases adopt a P(-)3m structure at room temperature and show positive thermal expansion. Both phases also undergo a displacive phase transition at high temperature (ZrMo(2)O(8) at 487 K and HfMo(2)O(8) at 463 K) to a higher-symmetry structure that has lower thermal expansion. The structure of the high-temperature alpha'-AMo(2)O(8) form (A = Zr and Hf) has been refined from powder diffraction data in space group P(-)3m1.
authors.affiliation: Department of Chemistry, University of Durham, Science Laboratories, South Road, Durham DH1 3LE, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Allen
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Ward
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hampson
authors.forename: Richard K B
authors.initials: RK
authors.lastname: Gover
authors.forename: John S O
authors.initials: JS
authors.lastname: Evans