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Groeneveld JD, Burianek M, Birkenstock J, Fischer LA, Shannon RD, Fischer RX. Synthesis, revised crystal structures, and refractive indices of ABW-type CsMTiO4 (M = Al, Fe, Ga) and ANA-type CsTi1.10Si1.90O6.50, and the determination of the electronic polarizability of 4-coordinated Ti4+. Z KRIST-CRYST MATER 2020. [DOI: 10.1515/zkri-2020-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Single crystals of ABW-type CsAlTiO4 (CAT), CsFeTiO4 (CFT), CsGaTiO4 (CGT), and ANA-type CsTi1.1Si1.9O6.5 (CST) were grown and characterized by electron microprobe analyses, single-crystal X-ray diffraction, thermal analyses, and spindle-stage optical investigations to determine the electronic polarizability of 4-coordinated Ti4+, α([4]Ti4+). The crystal structure of CAT was confirmed to crystallize in the highest possible topological symmetry Imma (a = 8.9677(2) Å, b = 5.7322(1) Å, c = 9.9612(3) Å) with tetrahedrally coordinated Al and Ti equally distributed on Wyckoff position 8i. Twinning by reticular merohedry with a twin index of 2 was observed for most of the crystals resulting in a hexagonal twin lattice (a = 11.487(3) Å, c = 8.968(2) Å) with Laue symmetry 6/mmm. Refractive indices measured by immersion methods on an untwinned specimen are n
x = 1.716(5), n
y = 1.725(2), and n
z = 1.727(1) with 2V
z = 127.1(6)°. The diffraction patterns of CFT and CGT clearly showed superstructure reflections causing a symmetry lowering of index 4 with a transformation according to 2a, b, c from Imma to Pmab with a = 18.3054(7) Å, b = 5.8083(2) Å, c = 9.9938(4) Å for CFT, and a = 18.2921(6) Å, b = 5.7636(2) Å, c = 9.9210(3) Å for CGT. Refractive indices for CGT are n
x = 1.750(3), n
y = 1.772(3), and n
z = 1.776(2) with 2V
z = 132(1)°. The crystal structure of the ANA-type CsTi1.1Si1.9O6.5 was confirmed to crystallize in space group Ia
3
¯
$\overline{3}$
d (a = 13.8333(4) Å). The extra 0.5 O atoms are needed for charge compensation and to allow the sum of electronic polarizabilities to give a total electronic polarizability calculated from the refractive index n = 1.718(4). The electronic polarizability of [4]Ti4+ was calculated from the difference between the observed total polarizabilities (derived from the mean refractive indices of CAT and CGT) and the sum of electronic polarizabilities of cations and anions omitting the polarizability of Ti resulting in α([4]Ti4+) = 5.15(5) Å3.
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Affiliation(s)
- Jan Derk Groeneveld
- Universität Bremen, FB 5 Geowissenschaften , Klagenfurter Str. 2 , 28359 Bremen , Germany
| | - Manfred Burianek
- Universität Bremen, FB 5 Geowissenschaften , Klagenfurter Str. 2 , 28359 Bremen , Germany
| | - Johannes Birkenstock
- Universität Bremen, FB 5 Geowissenschaften , Klagenfurter Str. 2 , 28359 Bremen , Germany
| | - Lennart A. Fischer
- Institut für Geo- u. Umweltnaturwissenschaften, Geochemie, Albert-Ludwigs-Universität Freiburg , Albertstraße 23b , 79104 Freiburg , Germany
| | - Robert D. Shannon
- Geological Sciences CIRES, University of Colorado , Boulder , Colorado 80309, USA
| | - Reinhard X. Fischer
- Universität Bremen, FB 5 Geowissenschaften , Klagenfurter Str. 2 , 28359 Bremen , Germany
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Bugaris DE, zur Loye HC. Auf der Suche nach neuen Materialien: Kristallzucht von quaternären und höherwertigen Oxiden in Flussmitteln. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201102676] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Bugaris DE, zur Loye HC. Auf der Suche nach neuen Materialien: Kristallzucht von quaternären und höherwertigen Oxiden in Flussmitteln. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201102676 and doi:10.1002/anie.201102676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Materials Discovery by Flux Crystal Growth: Quaternary and Higher Order Oxides. Angew Chem Int Ed Engl 2012; 51:3780-811. [DOI: 10.1002/anie.201102676] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Indexed: 11/07/2022]
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