title: Barium-deficient celsian, Ba1-xAl2-2xSi2+2xO8 (x = 0.20 or 0.06).
abstract: Barium-deficient forms of celsian (barium aluminium silicate) with the formula Ba(1-x)Al(2-2x)Si(2+2x)O(8) (x = 0.20 and 0.06) have been identified. In contrast with the celsian-orthoclase solid solutions which have been reported previously, these forms, refined in the space group C2/m, with Ba and one O atom in the 4i sites with m site symmetry, and a further O atom in a 4g site with twofold axial symmetry, suggest a slight solid solution with silica. The serendipitous preparation of the compounds represents a possible hazard associated with solid-state synthesis.
authors.affiliation: Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Skellern
authors.forename: R Alan
authors.initials: RA
authors.lastname: Howie
authors.forename: Eric E
authors.initials: EE
authors.lastname: Lachowski
authors.forename: Janet M S
authors.initials: JM
authors.lastname: Skakle