In:
Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials, International Union of Crystallography (IUCr), Vol. 72, No. 1 ( 2016-02-01), p. 109-116
Abstract:
Single-crystal X-ray diffraction of Cs 3 ScSi 6 O 15 shows the presence of main reflections and satellite reflections up to the fourth order along the c* direction. The (3+1)-dimensional incommensurately modulated structure was solved in superspace group X{\bar 3}m1(00\gamma)0s0 [ a = 13.861 (1), c = 6.992 (1) Å, V = 1163.4 (2) Å 3 ] with a modulation wavevector q = 0.14153 (2) c* . Refinement of three modulation waves for positional and anisotropic displacement parameter values for all atoms converged to R obs values for all, main and satellite reflections of first, second and third order of 0.0200, 0.0166, 0.0181, 0.0214 and 0.0303, respectively. Cs 3 ScSi 6 O 15 forms a mixed tetrahedral–octahedral framework with prominent six-membered rings of [SiO 4 ]-tetrahedra interconnected by [ScO 6 ]-octahedra. Apart from Sc, all atoms are strongly affected by positional modulation with maximum atomic displacements of up to 0.93 Å causing rigid polyhedral arrangements to perform tilt and twist movements relative to each other, such as a rotation of the Sc-octahedra around the \bar 3-axis by over 38°. Cs has an irregular coordination environment; however, considering distances up to 3.5 Å, the bond-valence sum changes by no more than 0.02 as a function of t and thus overall kept at a level of ca 1.075.
Type of Medium:
Online Resource
ISSN:
2052-5206
DOI:
10.1107/S2052520615022076
DOI:
10.1107/S2052520615022076/dk5038sup1.cif
DOI:
10.1107/S2052520615022076/dk5038sup2.pdf
Language:
Unknown
Publisher:
International Union of Crystallography (IUCr)
Publication Date:
2016
detail.hit.zdb_id:
2020841-8
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