High temperature–high pressure synthesis and crystal structure of the incommensurately modulated, α-PbO2 related, compound MnTa2O6

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)00122-5

Cited by 11 publications

(13 citation statements)

References 15 publications

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“…2 shows the X-ray diffraction patterns of the (1 À x)ZnTa 2 O 6 -xTiO 2 ceramics sintered at 1250°C for 2 h. By indexing the patterns, we identified four structural types: tri-aPbO 2 , a-PbO 2 , trirutile, and rutile. a-PbO 2 -type (a-PbO 2 , tri-a-PbO 2 , columbite) structures exhibit distorted hexagonal close packing (hcp) of oxygen atoms with half of the octahedral sites filled, and infinite zigzag chains of edgesharing octahedra perpendicular to the unique hcp axis, connected via corner sharing [20]. The tri-a-PbO 2 structure is an ordered variant of the a-PbO 2 structure.…”

Section: Methodsmentioning

confidence: 99%

Crystal structure and microwave dielectric properties of (1−x)ZnTa2O6–xTiO2 ceramics

Park

Nahm

Park

2012

Journal of Alloys and Compounds

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Section: Methodsmentioning

confidence: 99%

Crystal structure and microwave dielectric properties of (1−x)ZnTa2O6–xTiO2 ceramics

Park

Nahm

Park

2012

Journal of Alloys and Compounds

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“…A year later, this polymorphism was found to be even richer with the discovery of a new hightemperature modification of MnTa 2 O 6 (Tarakina et al, 2003). The crystal structure of this last phase is incommensurately modulated.…”

Section: Introductionmentioning

confidence: 99%

A new approach for the determination of multiple cation locations and ordering, using the example of natural and heat-treated columbites

Kinast¹,

Isnard²,

Cunha³

et al. 2011

J Appl Cryst

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A new approach is proposed to determine unambiguously the location of four cations within the crystal structure of a natural AB 2 O 6 columbite-type compound and derivatives, when submitted to order-disorder transitions caused by heat treatments. This method is based on the successive use of electron microprobe analysis to determine the cation concentration, Mö ssbauer spectroscopy to identify the Fe occupation, and a crystal structure determination of the samples combining Rietveld refinements of both neutron and X-ray diffraction. This approach is tested successfully to investigate (Fe, Mn, Nb, Ta) natural minerals as well as oxides obtained by heat treatment of the initial AB 2 O 6 columbite-type compound.

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“…On the one hand, this limits the symmetrical capacity of the superspace model; on the other hand, the lower symmetry derived from the superspace group points to the probability of lower symmetry under some specific conditions. Indeed, the HT-HP-modification of MnTa 2 O 6 exhibits a monoclinic symmetry [22], while the room temperature modification [31] is isotypic with the orthorhombic a-PbO 2 .…”

Section: The A-pbo 2 -Z (3+ 1)-dimensional Structure Typementioning

confidence: 99%

“…First was the high-temperature and high-pressure (HT-HP) modification of MnTa 2 O 6 , which has been reported [22] as an incommensurately modulated structure with similar atomic coordinates ( Table 3). The LNZO and HT-HPMnTa 2 O 6 structures differ by the modulation vector q, which is equal to À 0.1038a* + 0.691b* for the incommensurately modulated MnTa 2 O 6 and 0.3a* +1.1b* for the commensurately modulated LZNO.…”

Section: The A-pbo 2 -Z (3+ 1)-dimensional Structure Typementioning

confidence: 99%

“…By analogy, the a-PbO 2 related compounds described with the P112 1 /n(ab0)00 superspace group can be referred to the a-PbO 2 -Z (3+ 1)D structure type, where Z specifies the c monoclinic axis inherited from the Pbcn space group characteristic of a-PbO 2 . In contrast to that, there is a group of a-PbO 2 related compounds, such as wolframites, AWO 4 (A=Mn, Fe, Cu, Zn), Wodginites, MnA(Nb,Ta) 2 O 8 (A =Sn, Ta, Ti, Fe, Li, Zr) [22], with the b monoclinic axis inherited from the a-PbO 2 space group. This group could be described in the a-PbO 2 -Y (3+ 1)D structure type, probably with P12/c1(a0g)00 superspace group.…”

Section: The A-pbo 2 -Z (3+ 1)-dimensional Structure Typementioning

confidence: 99%

See 1 more Smart Citation

LiZnNb4O11.5: A novel oxygen deficient compound in the Nb-rich part of the Li2O–ZnO–Nb2O5 system

Морозов

Arakcheeva

Konovalova

et al. 2010

Journal of Solid State Chemistry

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a-PbO 2 related structure Superspace approach Supercell (3+ 1)D structure type X-ray diffraction Transmission electron microscopy a b s t r a c t A novel lithium zinc niobium oxide LiZnNb 4 O 11.5 (LZNO) has been found in the Nb-rich part of Li 2 O-ZnO-Nb 2 O 5 system. LZNO, with an original a-PbO 2 related structure, has been synthesized by the routine ceramic technique and characterized by X-ray diffraction and transmission electron microscopy (TEM). Reflections belonging to the LZNO phase, observed in X-ray powder diffraction (XRPD) and electron diffraction, have been indexed as monoclinic with unit cell parameters a =17.8358(9)Å, b=15.2924(7)Å, c=5.0363(3)Å and g=96.607(5)1 or as a-PbO 2 -like with lattice constants a=4.72420(3)Å, b=5.72780(3)Å, c=5.03320(3)Å, g=90.048(16)1 and modulation vector q=0.3a*+1.1b* indicating a commensurately modulated a-PbO 2 related structure. The monoclinic cell is a supercell related to the latter. Using synchrotron powder diffraction data, the structure has been solved and refined as a commensurate modulation (superspace group P112 1 /n(ab0)00) as well as a supercell (space group P2 1 /b). The superspace description allows us to consider the LZNO structure as a member of the proposed a-PbO 2 -Z (3 + 1)D structure type, which unifies both incommensurately and commensurately modulated structures. HRTEM reveals several types of defects in LZNO and structural models for these defects are proposed. Two new phases in Li 2 O-ZnO-Nb 2 O 5 system are predicted on the basis of this detailed HRTEM analysis.

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High temperature–high pressure synthesis and crystal structure of the incommensurately modulated, α-PbO2 related, compound MnTa2O6

Cited by 11 publications

References 15 publications

Crystal structure and microwave dielectric properties of (1−x)ZnTa2O6–xTiO2 ceramics

Crystal structure and microwave dielectric properties of (1−x)ZnTa2O6–xTiO2 ceramics

A new approach for the determination of multiple cation locations and ordering, using the example of natural and heat-treated columbites

LiZnNb4O11.5: A novel oxygen deficient compound in the Nb-rich part of the Li2O–ZnO–Nb2O5 system

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