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Rietveld Analysis and Raman Spectroscopic Investigations on α‐Y 2 Si 2 O 7
Author(s) -
Kahlenberg V.,
Wertl W.,
Többens D. M.,
Kaindl R.,
Schuster P.,
Schottenberger H.
Publication year - 2008
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200700548
Subject(s) - crystallography , raman spectroscopy , triclinic crystal system , octahedron , silicate , rietveld refinement , crystal structure , powder diffraction , crystallite , materials science , x ray crystallography , chemistry , diffraction , physics , optics , organic chemistry
Polycrystalline material of α‐Y 2 Si 2 O 7 has been obtained from the thermal decomposition of a precursor prepared by a sol‐gel process and subsequently characterized by X‐ray powder diffraction and Raman spectroscopy. The structure belongs to the so‐called B‐type of rare earth element disilicates and was refined using the Rietveld method. α‐Y 2 Si 2 O 7 is triclinic with a = 6.58620(3), b = 6.62895(4), c = 12.02723(7) Å, α = 94.4706(4)°, β = 89.0681(4)°, γ = 88.2347(4)°, V = 523.166(5) Å 3 , space group $P{\bar 1}$ , Z = 4 and D x = 4.39 g/cm 3 . The structure (R wp = 4.7 %, R B = 2.9 %) is built from triple tetrahedral [Si 3 O 10 ]‐groups and isolated [SiO 4 ]‐units, i.e. from a structural point of view it belongs to the group of mixed anion silicates. The silicate anions are located in layers parallel to (1 ${\bar 1}$ 1). Linkage between the anionic groups is provided by Y cations having six and eight oxygen neighbours. The corresponding coordination polyhedra can be approximately described as distorted octahedra as well as bicapped trigonal prisms, respectively.