Two structure types based on Si<sub>6</sub>O<sub>15</sub> rings

Author(s)
Maria Wierzbicka-Wieczorek, Martin Göckeritz, Uwe Kolitsch, Christoph Lenz, Gerald Giester
Abstract

The silicate Cs

1.86K

1.14DySi

6O

15 represents a mixed tetrahedral-octahedral framework structure type based on roughly circular Si

6O

15 rings and isolated DyO

6 octahedra. The silicate Cs

1.6K

1.4SmSi

6O

15 has a layered atomic arrangement built from corrugated Si

6O

15 layers containing four-, six- and eight-membered rings. The layers are connected by isolated SmO

6 octahedra to form a mixed tetrahedral-octahedral framework. This structure shows a close structural relationship to β-K

3NdSi

6O

15 and a less close one to dehydrated elpidite (Na

2ZrSi

6O

15). In both structures, Cs/K atoms occupy large voids. The silicates were obtained through higherature flux syntheses. Their crystal structures have been determined from single-crystal X-ray diffraction data. Cs

1.86K

1.14DySi

6O

15 crystallises in R32 (no. 155) with a = 13.896(2), c = 35.623(7) Å and V = 5957.2(17) Å

3, whereas Cs

1.6K

1.4SmSi

6O

15 crystallises in Cmca (no. 64) with a = 14.474(3), b = 14.718(3), c = 15.231(3) Å and V = 3244.7(11) Å

3. The Dy

3+ and Sm

3+ cations present in the silicates cause PL emission bands in the visible yellow-to-orange spectral range. Two (Cs,K)-REE

3+ silicates (REE

3+ = Dy or Sm) containing Si

6O

15 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 REE

3+ cations in the structures causes emission bands in the visible yellow-to-orange spectral range.

Organisation(s)
Department of Mineralogy and Crystallography
External organisation(s)
Naturhistorisches Museum Wien (NHM), Friedrich-Schiller-Universität Jena
Journal
European Journal of Inorganic Chemistry
Volume
2015
Pages
2426-2436
No. of pages
11
ISSN
1434-1948
DOI
https://doi.org/10.1002/ejic.201500091
Publication date
04-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
104011 Materials chemistry, 105113 Crystallography
Keywords
ASJC Scopus subject areas
Inorganic Chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/1dd76d7f-2115-4d1c-a766-3fddd9a7b258