title: CsTe2O(6-x): novel mixed-valence tellurium oxides with framework-deficient pyrochlore-related structure.
abstract: Structures of CsTe₂O(6-x) phases were investigated by single-crystal X-ray diffraction and neutron powder diffraction. Stoichiometric CsTe₂O₆ is a mixed-valence Cs₂Te⁴⁺Te₃⁶⁺O₁₂ compound with a rhombohedral pyrochlore-type structure where there is complete order of Te⁴⁺ and Te⁶⁺. On heating, this compound develops significant electrical conductivity. As CsTe₂O₆ becomes oxygen deficient above 600 °C, the rhombohedral pyrochlore-type structure is replaced by a cubic pyrochlore-type structure with disordered Te⁴⁺/Te⁶⁺ and oxygen vacancies. However, for CsTe₂O(6-x) phases prepared at 500 °C, the observed pyrochlore-type structure has symmetry. The Te⁴⁺ and O vacancies are all on chains running along the b axis, and the maximum value of x observed is about 0.3. At still higher values of x a new compound was discovered with a structure related to that reported for Rb₄Te₃⁴⁺Te₅⁶⁺O₂₃.
authors.affiliation: Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Theeranun
authors.initials: T
authors.lastname: Siritanon
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Judith K
authors.initials: JK
authors.lastname: Stalick
authors.forename: Robin T
authors.initials: RT
authors.lastname: Macaluso
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Sleight
authors.forename: M A
authors.initials: MA
authors.lastname: Subramanian