Two Structure Types Based on Si6O15 Rings: Synthesis and Structural and Spectroscopic Characterisation of Cs1.86K1.14DySi6O15 and Cs1.6K1.4SmSi6O15

The silicate Cs1.86K1.14DySi6O15 represents a mixed tetrahedral‐octahedral framework structure type based on roughly circular Si6O15 rings and isolated DyO6 octahedra. The silicate Cs1.6K1.4SmSi6O15 has a layered atomic arrangement built from corrugated Si6O15 layers containing four‐, six‐ and eight...

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Bibliographic Details
Published in:European journal of inorganic chemistry 2015-05, Vol.2015 (14), p.2426-2436
Main Authors: Wierzbicka-Wieczorek, Maria, Göckeritz, Martin, Kolitsch, Uwe, Lenz, Christoph, Giester, Gerald
Format: Article
Language:English
Subjects:
Dysprosium
Flux synthesis
Mixed-framework silicates
Photoluminescence
Samarium
Silicates
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Summary:The silicate Cs1.86K1.14DySi6O15 represents a mixed tetrahedral‐octahedral framework structure type based on roughly circular Si6O15 rings and isolated DyO6 octahedra. The silicate Cs1.6K1.4SmSi6O15 has a layered atomic arrangement built from corrugated Si6O15 layers containing four‐, six‐ and eight‐membered rings. The layers are connected by isolated SmO6 octahedra to form a mixed tetrahedral‐octahedral framework. This structure shows a close structural relationship to β‐K3NdSi6O15 and a less close one to dehydrated elpidite (Na2ZrSi6O15). In both structures, Cs/K atoms occupy large voids. The silicates were obtained through high‐temperature flux syntheses. Their crystal structures have been determined from single‐crystal X‐ray diffraction data. Cs1.86K1.14DySi6O15 crystallises in R32 (no. 155) with a = 13.896(2), c = 35.623(7) Å and V = 5957.2(17) Å3, whereas Cs1.6K1.4SmSi6O15 crystallises in Cmca (no. 64) with a = 14.474(3), b = 14.718(3), c = 15.231(3) Å and V = 3244.7(11) Å3. The Dy3+ and Sm3+ cations present in the silicates cause PL emission bands in the visible yellow‐to‐orange spectral range. Two (Cs,K)‐REE3+ silicates (REE3+ = Dy or Sm) containing Si6O15 rings represent mixed tetrahedral‐octahedral framework structure types. Their crystal structures were characterised by single‐crystal X‐ray diffraction and photoluminescence spectroscopy. The presence of REE3+ cations in the structures causes emission bands in the visible yellow‐to‐orange spectral range.
ISSN:1434-1948
1099-0682
DOI:10.1002/ejic.201500091