High temperature/high pressure synthesis and crystal structure of the new corundum related compound Zn4Nb2O9

Tarakina, Nadezda V.; Tyutyunnik, A. P.; Зубков, В. Г.; D’yachkova, T. V.; Zainulin, Yury G.; Hannerz, Hillevi; Svensson, Gunnar

doi:10.1016/s1293-2558(03)00024-4

Cited by 16 publications

(9 citation statements)

References 9 publications

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“…At 1.867 (3) Å , the three Nb2-O1 bonds are much shorter than the Nb2-O2 bonds of 2.189 (5) Å , distorting the octahedra. This has also been observed in other face-sharing niobium systems (Tyutyunnik et al, 2002;Tarakina et al, 2003). As a result of metal-metal repulsion, the Nb2 atoms are shifted away from each other.…”

supporting

confidence: 69%

K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

2009

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Potassium scandium niobate hydroxide, K(3)(Sc(0.875)Nb(0.125))Nb(2)O(9)H(1.75), is a new scandium niobate with a unique cage structure. The structure contains two non-equivalent K(+) sites (3m and 6m2 site symmetry), one disordered Sc(3+)/Nb(5+) site (3m site symmetry), one Nb(5+) site (3m site symmetry), two O(2-) sites (m and mm2 site symmetry) and one H(+) site (m site symmetry). Both scandium and niobium have octahedral environments, which combine to form cages around potassium. One K atom lies in a cube-like cage built of seven octahedra, while the other K atom is encapsulated by an eight-membered trigonal face-bicapped prism. The cages form sheets that extend along the ab plane.

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supporting

confidence: 69%

K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

2009

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“…In a previous paper (Morniroli & Steeds, 1992) we proposed a systematic and general method valid for all crystal systems to identify the possible space groups of a crystal at a microscopic or a nanoscopic scale from a few specific zone axis microdiffraction patterns. The method, which was already applied to several cases (Redjaimia & Morniroli, 1994; Mateo et al , 1997; Huvé et al , 2000; Wei et al , 2000; Gomez‐Herrero et al , 2001; Ranjan et al , 2001; Meshi et al , 2002; Quarez et al , 2003; Tarakina et al , 2003; Meshi et al , 2005; Labidi et al , 2005), requires the observation of the first‐order Laue zone (FOLZ) and it is based on the identification of:…”

Section: Introductionmentioning

confidence: 99%

Electron precession microdiffraction as a useful tool for the identification of the space group

Morniroli

Redjaïmia

2007

Journal of Microscopy

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SummaryThe possible space groups of a crystal can be identified from a few zone axis microdiffraction patterns provided the position (and not the intensity) of the reflections on the patterns is taken into account. The method is based on the observation of the shifts and the periodicity differences between the reflections located in the first-order Laue zone (FOLZ) with respect to the ones located in the zero-order Laue zone (ZOLZ).Electron precession microdiffraction patterns display more reflections in the ZOLZ and in the FOLZ than in the conventional microdiffraction patterns and this number increases with the precession angle. It is shown, from the TiAl example given in the present study, that this interesting feature brings a strong beneficial effect for the identification of the possible space groups since it becomes very easy to identify unambiguously the FOLZ/ZOLZ shifts and periodicity differences. In addition, the diffracted intensity on the precession patterns is the integrated intensity and this intensity can also be used to identify the Laue class.

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“…The compound KCaVO 4 was synthesized from a mixture of KVO 3 (99.99%), K 2 CO 3 (99.99%) and Ca 3 (VO 4 ) 2 (99.99%) by a high-pressure high-temperature technique at P = 4 GPa, T = 1223 K for 2 min similar to the procedure described in (Tarakina et al, 2003). RbBaVO 4 was synthesized from a mixture of RbVO 3 (99.8%) and BaCO 3 (99.8%) by a conventional solidstate reaction at 650-700 ºC for 80 hours in air, with intermediate regrinding.…”

Section: Methodsmentioning

confidence: 99%

Crystal structure of RbBaVO₄ and high-pressure modification of KCaVO₄

et al. 2013

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The crystal structures of KCaVO 4 and RbBaVO 4 , synthesized at high-pressure/high-temperature and by a conventional solid-state reaction, respectively, were determined using X-ray powder diffraction data. These compounds were found to have the β-K 2 SO 4 structure type (space group Pnma, Z = 4) with parameters a = 7.2628(5) Å, b = 5.7258(4) Å, c = 9.6854(7) Å (KCaVO 4 ), and a = 7.8887(1) Å, b = 5.9589(1) Å, c = 10.3958(2) Å (RbBaVO 4 ). The unit cell volume of KCaVO 4 , 402.77(5) Å 3 , is significantly lower than for the low-temperature modification reported previously, 436.2 Å 3 . The difference can be explained by a pressure-induced phase transition to a more dense state resulting from the rotation of tetrahedra and the exchange of oxygen atoms from the first and second coordination spheres for potassium and calcium atoms.

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High temperature/high pressure synthesis and crystal structure of the new corundum related compound Zn4Nb2O9

Cited by 16 publications

References 9 publications

K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

Electron precession microdiffraction as a useful tool for the identification of the space group

Crystal structure of RbBaVO₄ and high-pressure modification of KCaVO₄

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High temperature/high pressure synthesis and crystal structure of the new corundum related compound Zn4Nb2O9

Cited by 16 publications

References 9 publications

K3(Sc0.875Nb0.125)Nb2O9H1.75: a new scandium niobate with a unique cage structure

K3(Sc0.875Nb0.125)Nb2O9H1.75: a new scandium niobate with a unique cage structure

Electron precession microdiffraction as a useful tool for the identification of the space group

Crystal structure of RbBaVO4 and high-pressure modification of KCaVO4

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K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

K₃(Sc_0.875Nb_0.125)Nb₂O₉H_1.75: a new scandium niobate with a unique cage structure

Crystal structure of RbBaVO₄ and high-pressure modification of KCaVO₄