A new layered perovskite, KSrNb2O6F, by powder neutron diffraction

作者：Yoo Chung Yul; Hong Kun Pyo; Kim Seung Joo^*

来源：Acta Crystallographica Section C-Crystal Structure Communications, 2007, 63: I63-I65.

DOI：10.1107/S0108270107029563

The structure of a new layered oxy uoride, viz. potassium strontium diniobium hexaoxide uoride, KSrNb2O6F, was re ned from powder neutron diffraction data in the orthorhombic space group Immm. The oxy uoride compound is an n = 2 member of the Dion-Jacobson- type family of general formula A[A'n-1BnX3n+ 1], which consists of double layered perovskite slabs, [ SrNb2O6F]., between which K+ ions are located. Within the perovskite slabs, the NbO5F octahedra are signicantly distorted and tilted about the a axis. A bondvalencesum calculation gives evidence for O/ F ordering in KSrNb2O6F, with the F. ions located in the central sites of the corner- sharing NbO5F octahedra along the b axis. All atoms lie on special positions, namely Nb on m, Sr on mmm, K on m2m, F on mm2, and O on sites of symmetry m and m2m.

• 出版日期2007-8