Studies on the System ZnO-V2O5-Fe2O3 Reactivity of ZnFe2O4 Towards ZnV2O6

Studies on the reactivity of ZnFe₂O₄ towards ZnV₂O₆ revealed that in the solid state the phases interact in a molar ratio of 1:3 to form a new compound, to which the molecular formula Zn₂FeV₃O₁₁ was assigned. The compound melts congruently at 825±5°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

The synthesis and selected properties of Co<Subscript>2</Subscript>InV<Subscript>3</Subscript>O<Subscript>11</Subscript>

It has been demonstrated that Co₂V₂O₇ and InVO₄ react with each other forming a new compound of the Co₂InV₃O₁₁ formula, when their molar ratio is equal to 1:1, or among CoCO₃, In₂O₃ and V₂O₅, mixed at a molar ratio of 4:1:3. This compound melts incongruently at the temperature of 960±5°C, depositing crystals of InVO₄. It crystallizes in the triclinic system and the unit cell parameters amount to: a=0.6524(6) nm, b=0.6885(5) nm, c=1.0290(4) nm, α=96.5°, β=104.1°, γ=100.9°, Z=2. The phase equilibria being established in the Co₂V₂O₇–InVO₄ system over the whole components concentration range up to the solidus line were described.     

Phase Equilibria in the V2O5-Sb2O4 System

Differential thermal analysis (DTA) and X-ray powder diffraction (XRD) were used to study phase equilibria, established in air in the V₂O₅-Sb₂O₄ system up to 1000°C. It has been found that there is a new phase =SbVO₅. The =SbVO₅ has been prepared by two methods: by heating equimolar mixtures of V₂O₅ and α-Sb₂O₄ in air and by oxidation of the known phase of rutile type obtained in pure argon at temperatures between 550 and 650°C. Thermal decomposition of =SbVO₅ in the solid state starts at 710°C giving off oxygen. The results provide a basis for constructing only a part of the phase diagram of the investigated system (up to 50.00 mol% Sb₂O₄). This revised version was published online in July 2006 with corrections to the Cover Date.     

Reactivity of FeVO4 towards MgMoO4 in the solid-state

A compound of the formula Fe₃Mg₂Mo₂V₃O₂₀ has been obtained as a result of a reaction between FeVO₄ and MgMoO₄ taken at a molar ratio of 3:2. This compound crystallises in the monoclinic system and its unit cell parameters are the following: a=0.6971 nm, b=0.9055 nm,c=1.2542 nm, g=102.00°, Z=2. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Relations in the CoMoO4-CoV2O6-CoO System Quasi-Binary Line Co3V2O8-CoMoO4

The phase relationship in the pseudobinary Co₃V₂O₈-CoMoO₄ system have been determined by differential thermal analysis (DTA) and X-ray diffraction (XRD). A new compound Co_2.5 VMoO₈, stable up to 1080±5°C has been found in the system. The results obtained are presented in the form of a phase diagram. This revised version was published online in July 2006 with corrections to the Cover Date.     

Unknown thermal properties of ZnSb2O6 and Zn7Sb2O12 compounds

The investigations by XRD, DTA/TG and IR methods show that two compounds: ZnSb₂O₆ and Zn₇Sb₂O₁₂ are formed in the ZnO-α-Sb₂O₄ system in air. Oxygen contained in the air participates in the synthesis of these compounds. ZnSb₂O₆ was observed as an intermediate phase, during the Zn₇Sb₂O₁₂ synthesis. The temperature of the β→α-Zn₇Sb₂O₁₂ transition was fixed at 1225±10°C. The mechanisms of the reactions of ZnSb₂O₆ and Zn₇Sb₂O₁₂ thermal decomposition have been proposed. The IR studies of α and β-Zn₇Sb₂O₁₂ have initially indicated that the structures of both polymorphous forms differ in the reciprocal connection of the SbO₆ and ZnO₆ octahedra and the ZnO₄ tetrahedra.     

Initial Studies on the Oxide System Cr2O3–Sb2O4

Differential thermal analysis (DTA) and X-ray diffraction (XRD) were utilized to study the phase equilibrium established in the subsolidus area of the system Cr₂ O₃ –Sb₂ O₄ . It was found that the components of the title system interact in ambient air to produce CrSbO₄ . The compound is stable up to ~1380°C, at which temperature it starts to decompose. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phase Relations in The Subsolidus Area of The CoV2O6–CoMoO4–CoO Subsystem Included by The Ternary CoO–V2O5–MoO3 System

The phase diagram of CoV₂O₆–CoMoO₄–CoO system in subsolidus area was investigated by DTA and XRD methods. It was shown that this area consisted of five subsidiary systems in which there existed three solid phases. The melting temperatures of these systems were also determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reactivity in The Solid State Between Ag2S and Ag2CrO4

Reactivity, in the solid state between Ag₂S and Ag₂CrO₄, was investigated by DTA, XRD and IR methods. It was found that, according to a composition of an initial Ag₂S/Ag₂CrO₄ mixture, the products of a reaction of Ag₂S with Ag₂ CrO₄ can be: solid solution with Ag₂CrO₄ structure (Ag₂Cr_1–xS_xO₄) and AgCrO₂; or solid solution Ag₂Cr_1–xS_xO₄, Ag₂SO₄, AgCrO₂ and metallic silver; or Ag₂S, β-Ag₈S₄O₄, Ag, AgCrO₂, Ag₂SO₄ and Ag₂Cr_1–xS_xO₄ solid solution. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and selected properties of Co3Fe4V6O24

A new compound Co₃Fe₄V₆O₂₄ has been obtained by solid state reaction. Temperature of its incongruent melting amounts to 890±5°C. Results of indexing the powder diffraction pattern and unit cell parameters of Co₃Fe₄V₆O₂₄ are also given. This compound is probably isostructural with M₃Fe₄V6O₂₄ (where M = Zn, Mg, Mn). IR spectrum of Co₃Fe₄V₆O₂₄ phase is presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase equilibria in the system NiO-V2O5-Fe2O3 in subsolidus area

Reactivity of FeVO₄ towards Ni₂V₂O₇ and Ni₃V₂O₈ in the solid state was investigated. On the base of XRD and DTA results, phase diagrams in subsolidus area of the FeVO₄-Ni₂V₂O₇ and FeVO₄-Ni₃V₂O₈ intersections of the ternary system NiO-V₂O₅-Fe₂O₃ have been worked out and the phase diagram of this ternary system in subsolidus area in the whole component concentration range has been verified. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Thermal Stability of Zn4V2O9

A study of synthesis and thermal decomposition of the Zn₄V₂O₉ have been conducted by XRD method using a high-temperature X-ray attachment. A melting temperature and the way of melting that compound have been established. This revised version was published online in July 2006 with corrections to the Cover Date.     

Subsolidus area of the AlVO4−Al2(MoO4)3 system

The behaviour of Al₂(MoO₄)₃ towards AIVO₄ in the subsolidus area, over the whole component concentration range, has been studied using the DTA and XRD methods. The experimental results have been presented in the form of a phase diagram. It has been found that components of the system of interest do not remain in equilibrium, and AlVO₄?Al₂(MoO₄)₃ system is not a real two-component system, even in the subsolidus area.     

Studies on the System AIVMoO7-V2O5

The phase equilibria in the system AlVMoO₇-V₂O₅ were investigated over the whole component concentration range up to 1000°C. A phase diagram was constructed from the results of DTA and XRD methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Crystal Structure and Chemical Reactivity of Heme Phenoxide Adducts

Abstract

A simple phenoxide heme compound has been fully structurally characterized for the first time. The crystal structure of a 2,6-dichlorophenoxy Fe(III) 5,10,15,20-tetraphenylporphyrin is reported and compared with the structure of simple aliphatic alkoxy aducts of Fe(III) porphyrins. It is further shown that phenoxy Fe porphyrins can promote regiospecific substitution (cyanation) of the bound phenol ring.     

ChemInform Abstract: V2O2F4 (H2O)2·H2O: A New V4+ Layer Structure Related to VOF3.

Single crystals of the title compound are prepared by hydrothermal reaction of VF₃ and H₂SeO₃ in ethylene glycol/HF (40%) in the presence of Et₂NH (autoclave, 393 K, 4 d).     

Phase relations in subsolidus area of ZnO-V2O5-Fe2O3 system

Phase equilibria in subsolidus area in the ZnO-V₂O₅-Fe₂O₃ system have been investigated over the whole concentration range of the oxides. The components of this system form two compounds: Zn₂FeV₃O₁₁ and Zn₃Fe₄(VO₄)₆. A solidus area projection onto the component concentration triangle plane of the ZnO-V₂O₅-Fe₂O₃ system has been constructed using DTA and XRD methods. 11 subsidiary subsystems can be distinguished in this system. Melting temperatures of mixtures of solid phases coexisting at equilibrium in each of subsidiary subsystems were determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase relations in the system ZnV2O6 -ZnFe2O4

Using DTA and XRD methods, a diagram of phase equilibria in ZnV₂O₆-ZnFe₂O₄ system has been constructed. System ZnV₂O₆-ZnFe₂O₄ is in subsolidus area a real binary system and its components form a compound Zn₂FeV₃O₁₁. Zn₂FeV₃O₁₁ melts incongruently at 835±5°C with deposition of two solid phases: b-Zn₂V₂O₇ and ZnFe₂O₄. This revised version was published online in July 2006 with corrections to the Cover Date.     

Si内标-X射线衍射法定量测定铁矿中Fe3O4、Fe2O3和SiO2

铁矿物相的准确定量对矿物价值评价及选冶工艺研究有重要作用,现有化学法流程复杂效率低,X射线衍射全谱拟合法可溯源性差,结果准确性难以评价和验证。本研究建立了以Si为内标,以Cu靶X射线为辐射光源,步进扫描方式获得衍射谱图,以待测相含量为横坐标,待测相与内标相峰面积比值为纵坐标建立校准曲线,以曲线对铁矿中Fe3O4、Fe2O3和SiO2物相进行定量的方法。试验对制样条件、扫描参数、内标物选择、积分方式、重叠峰校正等进行了优化选择,结果表明,试样全部通过45 μm标准筛,Si内标比例为10%,步进长度0.01°,步进时间30S,选择对Fe3O4（311）、Fe2O3（104）、SiO2（011）和Si（111）的衍射峰进行积分强度计算,可获得最优结果。在选定工作条件下,Fe3O4在1.07～100%范围内线性相关系数(R2)为0.9953,相对标准偏差(RSD)1.1%～13.2% (n=6),加标回收率99.7 %~114.8 %,检出限(LOD)4.29%;Fe2O3在1.51～100%范围内线性相关系数(R2)为0.9991,相对标准偏差(RSD)2.8%～10.6% (n=6),加标回收率87.1%~112.2%,检出限(LOD)2.56%;SiO2在0.79～29.72 %范围内线性相关系数(R2)为0.9957,相对标准偏差(RSD)3.2%～10.3% (n=6),加标回收率86.6%~98.9%,检出限(LOD)0.68%。方法易溯源、准确性易评价和验证,适合开展标准化检测和应用。