Sr9Ni6.64O21: A New Member (n= 2) of the Perovskite-RelatedA3n+3An′B3+nO9+6nFamily

Cation Deficiency in (Ba, Sr)Co1−xOyHexagonal Perovskite Related Oxides: New Members of theAn+2B′BnO3n+3Homologous Series

“…When M"Zn, a related incommensurate structure is observed. The first example of an n"2 phase has been reported by Campa´et al (11) for Sr Ni O , with some vacancies in prismatic sites. An n"3 phase Sr Ni O , in which half of the trigonal prismatic sites are occupied by Ni>, has been described by Strunk and Mu¨ller-Buschbaum (12).…”

Commensurate and Incommensurate Phases in the SystemA4A′Ir2O9(A=Sr, Ba;A′=Cu, Zn)

“…Other overall stoichiometries can be envisaged if the stacking sequence of (A AO ) and (A O ) layers is allowed to vary, and the general case may be written as (A AO ) L (A O ) (that is an (A O ) layer is inserted after every n (A AO ) layers); filling the octahedral and trigonal prismatic holes then leads to the composition A L> A L B L> O L> . A number of n"1 phases have been described previously, for example Ba Ni O (5) and Sr Co O (6) (these phases have A"B), and the first example of an n"2 phase was reported recently by Campa et al (7). Strunk (8) (8 days), 1250°C (2 days).…”

Electron Microscopy of a Family of Hexagonal Perovskites: One-Dimensional Structures Related to Sr4Ni3O9

“…Up to now, no compound of m'4 has been isolated. m is not always constant along the chains; therefore, the stacking sequence for Sr Ni O can be described as a sequence of octahedra sharing opposite faces, [Ni O ] dimeric and [Ni O ] dimeric groups, which are connected through trigonal prisms (10).…”