Rb4Mo21Se24 containing Mo12 and Mo15 clusters

Rubidium molybdenum selenide, Rb₄Mo₂₁Se₂₄, crystallizes in the trigonal space group R. Its crystal structure consists of a mixture of Mo₁₂Se₁₄Se₆ and Mo₁₅Se₁₇Se₆ cluster units in a 1:2 ratio. Both units are interconnected through Mo—Se bonds. The Rb⁺ cations occupy large voids between the different cluster units.     

Thiophene hydrodesulfurization on P?Mo, Si?Mo and Ti?Mo catalysts

Studies of the catalysts obtained by supporting P–Mo, Si–Mo and Ti–Mo heteropolyacids on anatase in thiophene hydrodesulfurization have revealed that the presence of HPA in the initial catalysts promotes the formation of the molybdenum state ensuring high reaction rates. A possibility for HPA synthesis when supporting paramolybdate on TiO₂, accounts for the great effect of the support on the properties of the catalyst.

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Mo（Ⅵ）－PAN与Mo（Ⅵ）－PAR体系的极谱性质对比研究

本文比较了Ｍｏ（Ⅵ）－１－（２－吡啶基偶氮）－２－萘酚（ＰＡＮ）与Ｍｏ（Ⅵ）－４（２－吡啶基偶氮）间苯二酚（ＰＡＲ）的极谱性质，讨论它们在作为吸附波试剂时的优缺点，以求得在选择络合剂时的感性和理性认识．本文还报道了Ｍｏ（Ⅵ）－ＰＡＮ－ＫＢｒＯ３吸附催化波体系，最佳实验条件，０．１ｍｏｌ／ＬＨＡｃ－－ＮａＡｃ，ｐＨ＝４．６，０．０１ｍｏｌ／ＬＫＢｒＯ３，２．５×１０－５ｍｏｌ／ＬＰＡＮ．峰电位为－０．７１Ｖ（ｖｓ．ＳＣＥ），检出限１×１０－９ｍｏｌ／Ｌ，线性范围０～６×１０－７ｍｏｌ／Ｌ     

Synthesis and Crystal Structure of the Novel Compound Mg4.5Pr79.5Mo126O312 Containing Mo3, Mo7 and Mo19 Clusters

The synthesis and crystal structure of the novel reduced molybdenum oxide Mg_4.5Pr_79.5Mo₁₂₆O₃₁₂ are presented. This compound crystallizes in the trigonal space group R-3 m with a = 11.3061(2) Å, c = 58.242(1) Å, V = 6447.5(2) Å³, and Z = 1. Refinements yield R(F ²) = 0.0433 and wR(F ²) = 0.0931 for 2827 unique reflections. The structure is built up from alternating slabs made up of molybdenum forming Mo₃, Mo₇ and Mo₁₉ clusters, praseodymium and oxygen atoms, and slabs containing isolated MoO₆ octahedra. The Pr³⁺ cations are localized either within the slabs or at their borderlines to ensure the cohesion between the slabs. Of the six crystallographically independent sites occupy by the Pr³⁺ cations, two of them also contain randomly about 15% and 20% of Mg²⁺ cations while the remaining four are fully occupied by the Pr³⁺ cations.     

Cs6Mo27S31: a novel ternary reduced molybdenum sulfide containing Mo9 and Mo18 clusters

The crystal structure of hexacaesium heptacosamolybdenum hentriaconta­sulfide, Cs₆Mo₂₇S₃₁, consists of a mixture of Mo₉S₁₁S₆ and Mo₁₈S₂₀S₆ cluster units in a 1:1 ratio. The units are connected through Mo—S bonds. Cs⁺ cations occupy large voids between the different cluster units.     

Desorption of99Mo from spent99Mo/99mTc generator

A simple method for desorption and purification of⁹⁹Mo from spent⁹⁹Mo/^99mTc generators is described. The alumina column was washed successively with 0.9% saline water, 35% H₂O₂, and then the⁹⁹Mo was eluted with 2M NH₄OH. Ammonia and residual H₂O₂ were removed by heating the eluate. Finally,⁹⁹Mo solution was passed through a 0.2 m membrane filter to remove precipitated aluminium hydroxide.     

Ag2.54Tl2Mo12Se15: a new structure type containing Mo6 and Mo9 clusters

The novel structure‐type Ag_2.54Tl₂Mo₁₂Se₁₅ (silver thallium molybdenum selenide) is built up of Mo₆Seⁱ₈Se^a₆ and Mo₉Seⁱ₁₁Se^a₆ cluster units in a 1:2 ratio, which are three‐dimensionally connected to form the Mo–Se network. The Ag and Tl cations are distributed in several voids within the cluster network. Three of the seven independent Se atoms and one Tl atom lie on sites with 3.. symmetry (Wyckoff sites 2c or 2d).     

Rb5Mo27Se31, a novel ternary reduced molybdenum selenide containing Mo12 and Mo15 clusters

The crystal structure of Rb₅Mo₂₇Se₃₁, penta­rubidium hepta­cosa­molybdenum hentria­conta­selenium, consists of a mixture of Mo₁₂Se₁₄Se₆ and Mo₁₅Se₁₇Se₆ cluster units in a 1:1 ratio. Both types of cluster are interconnected through inter‐unit Mo—Se bonds. Rb⁺ cations occupy large voids between the different cluster units.     

Cs2Mo15S19: a novel ternary reduced molybdenum sulfide containing Mo6 and Mo9 clusters

The crystal structure of dicaesium pentadecamolybdenum nonadeca­sulfide, Cs₂Mo₁₅S₁₉, consists of a mixture of Mo₆S₈S₆ and Mo₉S₁₁S₆ cluster units in a 1:1 ratio. Both units are interconnected via inter‐unit Mo—S bonds. The Cs⁺ cations occupy large voids between the different cluster units. The Cs and two inner S atoms lie on sites with 3 symmetry (Wyckoff site 12c) and the Mo and S atoms of the median plane of the Mo₉S₁₁S₆ cluster unit on sites with 2 symmetry (Wyckoff site 18e).     

Quantum-chemical calculations of molybdenum chloride clusters Mo13C24, Mo13Cl26, and Mo13Cl30

Quantum-chemical calculations of the structures and thermodynamic stabilities of isomers of molecular clusters of lower Mo chlorides Mo₁₃Cl₂₄, Mo₁₃Cl₂₆, and Mo₁₃Cl₃₀, as well as of the Mo₁₃Cl ₂₆ ^? anion of cuboctahedral or icosahedral structure, have been performed by the DFT B3LYP method with the use of the Lanl2dz basis set for the Mo atoms and the 631G(d) basis set for the Cl atoms. The highest symmetry polyhedra are considered: Mo₁₃Cl₃₀ and Mo₁₃Cl₂₄ have a structure of centered icosahedron and cuboctahedron with bridging Cl atoms sitting atop the midpoints of 30 and 24 edges, respectively. In both cases, calculations lead to a rapid increase in the Mo-Mo distance to the values that are evidence of the absence of metal-metal bonds; hence, the cluster structure, in its classical meaning, is not retained. Both the neutral cluster Mo₁₃Cl₂₆ and the Mo₁₃Cl ₂₆ ^? anion—a symmetric icosahedron, in which Cl ions sit atop the centers of 20 faces and 6 Cl atoms are terminal, and a cuboctahedron, in which 14 Cl atoms are located on the three- and fourfold axes over the centers of molybdenum faces and 12 terminal Cl atoms are located on twofold axes. For both the neutral cluster and the anion, stable structures have been obtained. In both cases, the total energies are lower for the initial icosahedral configuration.     

浸渍法制备的Mo/ZSM-5催化剂中Mo的分布状态

 通过多晶XRD利用Rietveld方法测定和精修了浸渍法制备的Mo/ZSM-5催化剂样品的物相和晶体结构. 结果表明,Mo物种在ZSM-5分子筛中以3种形式存在. 一种是以［Mo5O12］6+形式存在于ZSM-5分子筛的孔道内,每个分子筛晶胞中平均含0.4个［Mo5O12］6+单元. 这些单元覆盖了分子筛孔道内的部分B酸中心,使其B酸量及总酸量减少,但使L酸量增加; ［Mo5O12］6+团中Mo的含量约占Mo/ZSM-5催化剂质量的3.03%. 其余的两种Mo物种分别以α-MoO3晶相和无定形氧化钼形式存在,修饰分子筛的外表面.     

Die Kristallstruktur des Komplexnitrides Mo(Ta,Mo)2N2

In the ternary system Ta/Mo/N a complex nitride of formula Mo(Ta,Mo)₂N₂ was observed at a nitrogen pressure of 360 bar and a temperature of 1,600°C. The crystal structure was determined from X-ray powder diagrams. The tetragonal unit cell, space groupI4/mmm-D _4h ¹⁷ , lattice parametersa=0.3051 nm,c=1.2530 nm contains ten atoms with an arrangement of the metal atoms corresponding to the MoSi₂-Type structure.