A refinement of the crystal structure of zinc molybdenum(IV) oxide, Zn2Mo3O8

Ansell, Gerald B.; Katz, Lawrence C

doi:10.1107/s0365110x66003359

Cited by 90 publications

(26 citation statements)

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“…The members of this group were prepared and examined systematically by McCarroll, Katz & Ward (1957) who reported that the compounds were isostructural because of the similar characteristics of their X-ray powder diffraction patterns; they presented the results of structure determinations on Zn2Mo30 8 and Mg2Mo30 8. Later a refinement of the structure was accomplished by Ansell & Katz (1966) on Zn2Mo3Os, confirming the previously reported structural features. The result is used as the basis for the present work on Fe2Mo308 (kamiokite).…”

supporting

confidence: 71%

Structure of kamiokite

Kanazawa¹,

Sasaki²

1986

Acta Crystallogr C

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Fig. 4 shows the DTA curve recorded between 240 and 130K. A small endothermic peak occurs at 168 (2)K. The peak is completely reversible with a slight hysteresis of about 5 K. Because the base line is not completely linear an exact value for the change in free enthalpy and consequently in the entropy should not be estimated. The peak in the DTA curve lies in the same temperature range as observed in the magnetic susceptibility curve (Fig. 3).The structure of the title compound shows an unusual connection scheme with edge-and face-sharing octahedra. This leads to distorted V(S,Se) 6 octahedra with short metal-metal bonds in the structure. The partial itinerant character of this compound is supported by the magnetic measurements. The discontinuity in the magnetic-susceptibility curve and the endothermic peak in the DTA curve are a clear indication for a phase transition at around 170K. Further investigations are in progress to clarify the nature of this phase transition.

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supporting

confidence: 71%

Structure of kamiokite

Kanazawa¹,

Sasaki²

1986

Acta Crystallogr C

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“…showing this behaviour (Cotton, 1977), for its lowvalent chemistry is characterized by numerous metalmetal bonded compounds which contain Mo clusters of various sizes such as Mo 2 dumb-bells [MoCI 3 (von Schnering & W6hrle, 1963); MoS2CI 3 (Marcoll, Rabenau, Mootz & Wunderlich, 1974)], Mo 3 triangles [Zn2Mo3Os (Ansell & Katz, 1966); MoN (Vandenberg & Matthias, 1974); Mo3S7C14 (Marcoll, Rabenau, Mootz & Wunderlich, 1974)], Mo4 tetrahedra [GaMo4S s (Perrin, Chevrel & Sergent, 1975a;Vandenberg & Brasen, 1975); MoSBr (Perrin, Chevrel & Sergent, 1975b)1, Mo 5 square-pyramids {[ (n-C4H9)aN]2Mo5CI13 (J6dden, von Schnering & SchS.fer, 1975)} and Mo 6 octahedra [MoCI 2 (Sch~ifer, von Schnering, Tillack, Kuhnen, W6hrle & Baumann, 1967); Mo3Se 4 (Bars, Guillevic & Grandjean, 1973)1. Compounds with clusters containing more than six Mo atoms, however, have not been found so far, and neither have substances been reported in which more than one transition-metal cluster species occurs in the same compound.…”

Section: Introductionmentioning

confidence: 99%

In∼3Mo15Se19, containing isolated Mo6 and Mo9 clusters

Grüttner¹,

Yvon²,

Chevrel³

et al. 1979

Acta Crystallogr Sect B

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The structure of In~3MOl5Sel9 has been determined by single-crystal X-ray diffraction analysis and refined for two different In concentrations. Space group P63/m, Z = 2, a = 9.804 (5) and 9.830 (5) A, c = 19.49 (1) and 19.40 (1) A, for In2.9MolsSe19 and In3.3MOlsSe19, respectively. The key structural elements are Mo6Se 8 and Mo9Sell building blocks which are stacked in the sequence ABAC and are separated by In atoms occupying statistically two types of interstices in the Seatom network. While the geometry of the Mo6Se 8 unit is identical to the one found in the rhombohedral MMo6X 8 compounds (M = metal, X = S, Se, Te), the Mo9Sell unit represents a new structural element which may be regarded as resulting from the fusion of two Mo6Se 8 units. It contains a Mo-atom cluster which is formed by nine Mo atoms occupying the vertices of a slightly elongated confacial bioctahedron. The variation of the In concentration leads to significant changes in the metal-metal bond lengths of the Mo 6 and MO 9 clusters.

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“…OEt )20 (10) are shown inFigure 1and reveal a striking similarity to both the [Ti(0Et)" structure and the structures of isopoly and heteropolyacids of molybde num, tungsten and vanadium.…”

mentioning

confidence: 83%

“…In the mixed oxo alkoxides of formula Mo 3 (0)(0R) 10 where R = CH 2 -t-Bu and i-Pr, the Mo-Mo distance is 2.535 A (averaged) (23), which may be compared with Mo-Mo = 2.524(2) R (averaged) in Zn 2 Mo 3 0 8 (19,20). The coordination about the molybdenum atoms is similar, but not the same for these triangulo complex es as is shown in Figure 2.…”

Section: Structural Andmentioning

confidence: 99%

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Metal Alkoxides: Models for Metal Oxides

Chisholm¹

1983

ACS Symposium Series

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In the spirit of this symposium, I should like to invite discussion of my proposal that metal alkoxides (1) may act as models for metal oxides in their reactions with a wide variety of hydrocarbons and small unsaturated molecules. Since metal oxides provide the most versatile class of heterogeneous catal ysts used in the petrochemical industry, studies of metal alkoxides, which are hydrocarbon soluble, could shed light on metal oxide catalyzed reactions and furthermore might yield a new generation of homogeneous catalysts. The fact that metal oxide catalysts are effective for reactions such as olefin -hydrogenation, -isomerization, -polymerization and -metathesis implies that metal-hydrogen and metal-carbon bonds are involved, perhaps in an analogous manner to those which are well documented in organometallic chemistry (2). This by itself is an interesting thought since metal oxides seem far removed from the now classical organometallic compounds which abound with ligands such as tertiary phosphines, carbonyls, π-bonded eyelopentadienes and arenes, etc. How can a metal-oxide environ ment compete with the sophisticated ligand systems that the contemporary organometallic chemist has available for catalyst design? Apparently, metal-oxide systems compete very effective ly and certainly in some instances there are no known homoge neous analogues. One can think of CO/H 2 activation in FischerTropsch chemistry as just one system in which the metal oxide catalysts win hands down over homogeneous metal-carbonyl chemis try Ο ). Let us speculate what special requirements a metal oxide environment or surface may provide. Factors which come to my mind include (i) unusual coordination numbers, geometries and electronic configurations for metal atoms; (ii) oxo ligands are strong π-donors, which contrast with most ligands commonly used in organometallic chemistry which are ιτ-acceptors; (iii) oxo ligands may act as terminal six-electron (M=0) or four-elec tron (M=0) ligands (4) or may act as bridging (μ 2 -> U3~> VU -, μ 5 -and μ 6 -) ligands and changes from one form to another may readily occur in response to the addition or elimination of

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A refinement of the crystal structure of zinc molybdenum(IV) oxide, Zn₂Mo₃O₈

Cited by 90 publications

References 2 publications

Structure of kamiokite

Structure of kamiokite

In∼3Mo15Se19, containing isolated Mo6 and Mo9 clusters

Metal Alkoxides: Models for Metal Oxides

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