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Crystal structures of Ca(4+x)Y(3–x)Si(7)O(15+x)N(5–x) (0 ≤ x ≤ 1) comprising of an isolated [Si(7)(O,N)(19)] unit
Single crystals of the solid solution series Ca(4+x)Y(3–x)Si(7)O(15+x)N(5–x) were obtained by a solid-state reaction method using a flux for x = 0, 0.5 and 1, resulting in Ca(4)Y(3)Si(7)O(15)N(5) (tetracalcium triyttrium heptasilicon oxynitride), Ca(4.5)Y(2.5)Si(7)O(15.5)N(4.5) and Ca(5)Y(2)Si(7)O...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
International Union of Crystallography
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6362659/ https://www.ncbi.nlm.nih.gov/pubmed/30800463 http://dx.doi.org/10.1107/S2056989019001257 |
Sumario: | Single crystals of the solid solution series Ca(4+x)Y(3–x)Si(7)O(15+x)N(5–x) were obtained by a solid-state reaction method using a flux for x = 0, 0.5 and 1, resulting in Ca(4)Y(3)Si(7)O(15)N(5) (tetracalcium triyttrium heptasilicon oxynitride), Ca(4.5)Y(2.5)Si(7)O(15.5)N(4.5) and Ca(5)Y(2)Si(7)O(16)N(4) (pentacalcium diyttrium heptasilicon oxynitride). Single-crystal X-ray analysis revealed that the three compounds are isotypic and belong to space-group type P6(3)/m. Ca(2+) and Y(3+) cations are distributed over two crystallographic sites (site symmetry [Image: see text].. and 1) in a disordered manner. The corresponding (Ca,Y)-centred polyhedra are connected by edge-sharing, resulting in the formation of a layer structure extending parallel to (001). Three [Si(O,N)](4) tetrahedra (two with point group symmetry m.., one with 3.. and half-occupancy) are condensed into an isolated [Si(7)(O,N)(19)] unit, in which an [Si(O,N)](4) tetrahedron is located at the center of a 12-membered oxynitride ring with composition [Si(6)O(15)N(3)]. The present compounds are the first to have such an [Si(7)(O,N)(19)] unit in their structures. |
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