Structure of kamiokite

Kanazawa, Yasuo; Sasaki, Takehiko

doi:10.1107/s0108270186097500

Cited by 13 publications

(8 citation statements)

References 7 publications

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“…The atomic coordinates of Fe2Mo30 s, also known as the mineral kamiokite, have been independently determined and refined by three different groups; the most recent values (Kanazawa & Sasaki, 1986) are given in Table 4. With lattice constants of a=5-781 (1), c= 10.060 (1)A at 298 K, refinement with 656 independent reflections IF o > 3tr (Fo)] based upon a model with anisotropic thermal parameters for all atoms gave R =0.027.…”

Section: Fe2mo3osfamilymentioning

confidence: 99%

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Abrahams¹

1988

Acta Crystallogr Sect B

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HIROYUKI TAKAZAWA, SHIGERU OHBA AND YOSHIHIKO SAITO 585 became lower and the deformation density decreased at the Pd nucleus and increased at the C1 nucleus. However, the charge asphericity due to the 4d electrons is not altered drastically. The change in deformation density based on (3) and (4) may be due to a tendency for IF al's to be slightly larger than I Fal's for the high-order reflections, and to the different sign of Af'(Mo Ka) for Pd and CI atoms. The error in anomalous-dispersion correction along with the error in scale factor makes the deformation density in the vicinity of the nuclear position of heavy atoms unreliable.The present study revealed that the very small valence/core electron ratio and large anomalous-dispersion effect of the heavy-metal atoms are not serious problems because the 4d electrons are distributed outside the high-density inner-core region and give sharp deformation density.This work was supported by the research grant of the Foundation 'Hattori Hokokai'. AbstractFerroelectricity may be predicted in any pyroelectric crystal that has atomic displacements along the polar axis no greater than about 1 A from the paraelectric position and in which the largest such displacement is greater than about 0

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Section: Fe2mo3osfamilymentioning

confidence: 99%

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Abrahams¹

1988

Acta Crystallogr Sect B

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“…This is longer than the mean FeÀO bond length of 199.3 pm in Fe II 2 Mo IV 3 O 8 , which exhibits Fe II O 4 tetrahedra as well. [38] In Co 6 B 22 O 39 ·H 2 O, the bond lengths of the six-coordinate cations vary from 200.4 to 250.2 pm with an average value of 212.9 pm. This value is in agreement with the average Co 2 + À O distance of six-coordinate cobalt atoms of 212.2 pm, found in Co 2 B 2 O 5 .…”

Section: Introductionmentioning

confidence: 99%

Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)

Neumair

Knyrim²,

Oeckler

et al. 2010

Chemistry A European J

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The new borates Fe(II)(6)B(22)O(39)·H(2)O (colourless) and Co(II)(6)B(22)O(39)·H(2)O (dichroic: red/bluish) were synthesised under the high-pressure/high-temperature conditions of 6 GPa and 880 °C (Fe)/950 °C (Co) in a Walker-type multi-anvil apparatus. The compounds crystallise in the orthorhombic space group Pmn2(1) (Z=2) with the lattice parameters a=771.9(2), b=823.4(2), c=1768.0(4) pm, V=1.1237(4) nm(3), R(1)=0.0476, wR(2)=0.0902 (all data) for Fe(6)B(22)O(39)·H(2)O and a=770.1(2), b=817.6(2), c=1746.9(4) pm, V=1.0999(4) nm(3), R(1)=0.0513, wR(2)=0.0939 (all data) for Co(6)B(22)O(39)·H(2)O. The new structure type of M(6)B(22)O(39)·H(2)O (M=Fe, Co) is built up from corner-sharing BO(4) tetrahedra and BO(3) groups, the latter being distorted and close to BO(4) tetrahedra if additional oxygen atoms of the neighbouring BO(4) tetrahedra are considered in the coordination sphere. This situation can be regarded as an intermediate state in the formation of edge-sharing tetrahedra. The structure consists of corrugated multiple layers interconnected by BO(3)/BO(4) groups to form Z-shaped channels. Inside these channels, iron and cobalt show octahedral (M1, M3, M4, M5) and strongly distorted tetrahedral (M2, M6) coordination by oxygen atoms. Co(II)(6)B(22)O(39)·H(2)O is dichroic and the low symmetry of the chromophore [Co(II)O(4)] is reflected by the polarised absorption spectra (Δ(t)=4650 cm(-1), B=878 cm(-1)).

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“…Later, a refinement of the structure was accomplished by Ansell & Katz (1966) with an R factor of 0.069. Among the above compounds, it is interesting to note that Fe 2 Mo 3 O 8 is a mineral known as kamiokite (Kanazawa & Sasaki, 1986 View of the crystal structure of Li 2 GeMo 3 O 8 in a projection approximately along [010]. Displacement ellipsoids are drawn at the 97% probability level.…”

Section: Database Surveymentioning

confidence: 99%

Li₂GeMo₃O₈: a novel reduced molybdenum oxide containing Mo₃O₁₃cluster units

Gall

Gougeon

2016

Acta Cryst E

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Structure of kamiokite

Cited by 13 publications

References 7 publications

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)

Li₂GeMo₃O₈: a novel reduced molybdenum oxide containing Mo₃O₁₃cluster units

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Structure of kamiokite

Cited by 13 publications

References 7 publications

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Structurally based prediction of ferroelectricity in inorganic materials with point group 6mm

Intermediate States on the Way to Edge‐Sharing BO4 Tetrahedra in M6B22O39⋅H2O (M=Fe, Co)

Li2GeMo3O8: a novel reduced molybdenum oxide containing Mo3O13cluster units

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Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)

Li₂GeMo₃O₈: a novel reduced molybdenum oxide containing Mo₃O₁₃cluster units