Chemical Vapor Transport of Ternary Cadmium Molybdates The ternary phase diagram Cd/Mo/O at 923 K have been investigated. Single crystals of CdMoO4 and Cd2Mo3O8 have been obtained via chemical vapor transport using X2 and NH4X (X = Cl, Br, I) as transport agent. Deposition rates are very different: up to 10 mg/h for CdMoO4, maximum 10–3 mg/h for Cd2Mo3O8. The observed transport behaviour is compared with results of thermodynamical model calculations. The influence of source composition, transport agent and temperature gradient is described in detail. 相似文献
On the Chemical Vapour Transport in the Mg/Mo/O System ‐ Experiments and Model Calculations Single crystals of MgMoO4 and Mg2Mo3O8 have been obtained via chemical vapour transport in a temperature gradient 1273 to 1173 K using Cl2 and Br2 as transport agents. Pure powders of the ternary compounds have been used as starting materials as well as mixtures of three coexisting phases. The observed transport behaviour is compared with results of thermodynamical model calculations. The influence of source composition, transport agent and the moisture contents is described in detail. 相似文献
Chemical Vapour Transport of Ternary Oxides in the Systems Ca/Mo/O and Sr/Mo/O The chemical vapour transport behaviour of ternary phases in the Ca/Mo/O and Sr/Mo/O systems has been investigated using Cl2 as transport agent in a temperature gradient 1423 to 1323 K. MMoO4 (M= Ca, Sr) migrate in the above‐mentioned temperature gradient with rates of 0.1 to 0.2 mg/h. Starting from three phase mixtures crystals of the compounds MMo5O8 have been grown (migration rates: M = Ca 0.1 mg/h, M = Sr 0.01 mg/h). The observed transport behaviour is compared with predictions given by thermo dynamical model calculations and the influences of source composition and the moisture contents are described in detail. 相似文献
Isothermal Section at 1273 K in the System Ti? Si? O The isothermal section at 1273 K of the system Ti? Si? O has been investigated by means of phase analysis in quenched samples as well as by the investigation of the phase sequence in chemical vapour transport experiments. In equilibrium with SiO2 only TiSi2, TiSi, and Ti5Si3(O), respectively, can coexist as Si-containing compounds. Only Ti5Si3(O) can coexist with titanium oxides (Ti2O3 or TiO, respectively). Ti5Si4 is stable only if oxygen is absent. 相似文献
On the Chemical Vapor Transport of Ternary Transition Metal‐ and Earth Alkaline Tungstates MWO4 with Chlorine The chemical vapor transport of transition metal tungstates MWO4 (M=Mn, Co, Ni, Cu, Zn, Cd) was investigated in dependence on mean transport temperature (923 K to 1223 K) and amount of transport agent Cl2. All tungstates migrate in a temperature gradient ΔT = 100 K from the region of higher temperature to the lower temperature with migration rates of 0.5 to 8 mg/h depending on experimental conditions. The transport behaviour was determined by continuous measurement of mass change during the transport experiments. The results were compared to thermo chemical calculations and the influence of moisture content discussed in detail. MgWO4 migrates under the influence of Cl2 in a temperature gradient 1273 K to 1173 K (migration rate 0.7 mg/h), CaWO4 and SrWO4 in a temperature gradient 1423 K to 1323 K (migration rate <0.1 mg/h). 相似文献
Coexistence Relations, Preparation and Properties of Ternary Compounds in the System Cu/Mo/O The phase diagram of the ternary system Cu/Mo/O is presented at 773 K. The compounds CuMoO4, Cu3Mo2O9, Cu4Mo5O17, Cu6Mo5O18, Cu4–xMo3O12, and CuxMoO3 are found to be thermodynamical stable. The homogeneity range of Cu4–xMo3O12 runs to x = 0.1–0.2. Single crystals of CuMoO4 and Cu3Mo2O9 were grown by chemical transport reactions with TeCl4, Cl2, HCl, and Br2 as transport agent. The results were compared with thermochemical calculations. The decomposition of CuMoO4 and Cu3Mo2O9 was investigated with thermal analysis and decompositon pressure measurements. 相似文献
The Ga2O3-Al2O3-ZnO (GAZ) multi-component spinel powders with incorporated Cu2+, Co2+, Fe2+, Ni2+, Mn2+ and In2+ metal cations were synthesized by co-precipitation method from a mixed solution of nitrate salts. Spinel crystal structure of each composition was confirmed by XRD measurements. The multi-component oxide powders were tested in the reduction of nitrogen oxide (NO) under lean conditions. Among the catalysts tested, In2O3-containing GAZ with a pure spinel phase structure showed promising catalytic activity in the NO reduction in the presence of 10% H2O vapor. In addition, the effect of H2O vapor and SO2 on the selective reduction of NO over In2O3-GAZ/cordierite and In2O3-GAZ/metal honeycombs catalysts has been investigated. 相似文献
Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXXIII [1] In2P2O7 an Indium(I)‐diphosphatoindate(III), and In4(P2O7)3 — Synthesis, Crystallization, and Crystal Structure Solid state reactions via the gas phase lead to the new mixed‐valence indium(I, III)‐diphosphate In2P2O7. Colourless single crystals of In2P2O7 have been grown by isothermal heating of stoichiometric amounts of InPO4 and InP (800 °C; 7d) using iodine as mineralizer. The structure of In2P2O7 [P21/c, a = 7.550(1) Å, b = 10.412(1) Å, c = 8.461(2) Å, b = 105.82(1)°, 2813 independent reflections, 101 parameter, R1 = 0.031, wR2 = 0.078] is the first example for an In+ cation in pure oxygen coordination. Observed distances d(InI‐O) are exceptionally long (dmin(InI‐O) = 2.82 Å) and support assumption of mainly s‐character for the lone‐pair at the In+ ion. Single crystals of In4(P2O7)3 were grown by chemical vapour transport experiments in a temperature gradient (1000 → 900 °C) using P/I mixtures as transport agent. In contrast to the isostructural diphosphates M4(P2O7)3 (M = V, Cr, Fe) monoclinic instead of orthorhombic symmetry has been found for In4(P2O7)3 [P21/a, a = 13.248(3) Å, b = 9.758(1) Å, c = 13.442(2) Å, b = 108.94(1)°, 7221 independent reflexes, 281 parameter, R1 = 0.027, wR2 = 0.067]. 相似文献
Chemical Transport of Solid Solutions. 8. Transport Phenomena and Ionic Conductivity in the In2O3/SnO2 System Chemical transport reactions are a suitable pathway to the preparation of In2O3‐rich and SnO2‐rich mixed crystals coexisting in the In2O3/SnO2 system (Cl2 as transport agent, 1050 → 900 °C). Experiments are consistent with thermodynamic calculations. The existence of other phases in the system In2O3/SnO2 could not be confirmed. The ionic conductivity of In2O3(SnO2) was investigated. 相似文献
The vapor pressure of pure liquid indium, and the sum of pressures of (In) and (In2O) species over the condensed phase mixture {In} + <In2O3>, contained in a silica vessel, have been measured by Knudsen effusion and Langmuir free vaporization methods in the temperatue range 600 to 950°C. Mass spectrometric studies reported in the literature show that (In) and (In2O) are the important species in the vapor phase over the {In} + <In2O3 >; mixture. The vapor pressure of (In2O) corresponding to the reaction, deduced from the present measurements is given by the equation, The “apparent evaporation coefficient” for the condensed phase mixture is approximately 0.8. The energy for the dissociation (In2O) molecule into atoms calculated from the above equation is D°0 = 180.0 (± 1.0) kcal mol?1. 相似文献
Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXIV. Preparation, Crystal Structure, and Properties of Copper(II) Indium(III) Orthophosphate Cu3In2[PO4]4 Crystals of Cu3In2[PO4]4 were grown by chemical vapour transport (temperature gradient 1273 K → 1173 K) using chlorine as transport agent. The mixed metal phosphate forms a new structure type (P21/c, Z = 2, a = 8.9067(6), b = 8.8271(5), c = 7.8815(5) Å, β = 108.393(5)°, 13 atoms in asymmetric unit, 2549 unique reflections with Fo > 4σ, 116 variables, R(F2) = 0.065). The crystal structure shows a hexagonal closest packing of [PO4]3– tetrahedra. Close‐packed layers parallel (1 0 –1) are stacked according to the sequence A, B, A′, B′, A. The octahedral interstices in this packing are completely occupied by two In3+, one (Cu1)2+ and a “dumb bell” (Cu2)24+. In the latter case four of the six phosphate groups that belong to this octahedral void act as bi‐dentate ligands, thus forming dimers [(Cu2)2O10] with dCu–Cu = 3.032 Å. Cu3In2[PO4]4 is paramagnetic (μeff = 1.89 μB, θP = –16.9 K). The infrared and UV/Vis reflectance spectra are reported. The observed d‐electron levels of the Cu2+ cations agree well with those obtained from angular overlap calculations. 相似文献
Vaporization of the system MgO-Al2O3-SiO2 in the temperature range 1770–1890 K was studied and activities of MgO and SiO2 were determined. Activities of the components, isothermal sections of the phase diagram, and the position of the liquidus
line in the studied system were calculated using the Gay-Kapoor-Frohberg model. The correlation of the found values of thermodynamic
properties and phase equilibriua in isothermal sections of the phase diagram of the studied system was illustrated. 相似文献
Thermal stability of a compound forming in a binary system MoO3?CIn2O3 was investigated by DTA/TG, XRD and SEM methods in this study. For the first time, the diagram of phase equilibria established in the whole range of concentrations of this system's components has been constructed. The temperature and concentration ranges of the components of MoO3?CIn2O3 system in which the compound In2(MoO4)3 co-exists in solid state with MoO3 or In2O3 or with the liquid were determined. The composition and melting point of the eutectic mixture consisting of In2(MoO4)3 and MoO3 were found. 相似文献
The Quaternary System ZnIn2S4? ZnIn2Se4? In2Se3? In2S3 The title system has been investigated on the indium rich side (ratio In/Zn ≥ 2) on samples quenched from 800°C to room temperature using x-ray methods. In this section 7 different phases could be identified the phase borders of which are given. ZnIn2S4-type and thiogallate type mixed crystals only show a small region of homogeneity while the monophase region of spinel type mixed crystals in the indiumsulfide rich part of the phase diagram has a larger extension. There is a new trigonal compound ZnIn2S2Se2 (ahex = 3.937, chex = 31.97 Å) with a large region of homogeneity. In the indiumselenide rich part there are two new phases: (i) Zn0.4In2Se3.4 with unknown structure and (ii) a ternary phase of unknown structure in the system In2S3?xSex for 2.1 ≤ x ≤ 2.7. 相似文献
As a conceptual study, In0 nanoparticles are obtained by NaBH4‐driven reduction of InCl3 · 4H2O and transferred from a polar/hydrophilic diethylene glycol phase to a non‐polar hydrophobic dodecane phase for purification and stabilization. Finally, the In0 nanoparticles are oxidized via a Laux‐like reaction with nitrobenzene to In2O3 nanoparticles. The challenge of the reaction is to perform the final oxidation to In2O3 under mild conditions with the colloidal stability, particle size and particle size distribution of the initial In0 nanoparticles retained. To this concern, the mean diameter of the initial In0 nanoparticles changed from 11(1) to 14(2) nm of the oxidized In2O3 nanoparticles. Such multi‐step reaction, including reduction, nucleation, phase transfer, exchange of surface capping and oxidation are of increasing importance for nanoparticles. Especially, Laux‐type conditions with nitrobenzene as a molecular oxidizing agent of nanoparticles have not been used till now. Particle size, size distribution and chemical composition of the In0 and In2O3 nanoparticles are analyzed by DLS, SEM, XRD, FT‐IR and HRTEM. 相似文献
Chemical Vapor Transport of Solid Solutions. 11 Mixed Phases and Chemical Vapor Transport in the Systems CrIII/InIII/GeIV/O, GaIII/InIII/GeIV/O, MnIII/InIII/GeIV/O und FeIII/InIII/GeIV/O By means of chemical vapor transport methods the following mixed phases have been prepared: Cr0, 18In1, 82Ge2O7 (Cl2, 950 → 850 °C), (Ga0, 6In1, 4)2Ge2O7 (Thortveitit‐type, Cl2, 1050 → 950 °C), (Ga1, 9In0, 1)2Ge2O7 (Ga2Ge2O7‐type, 1050 → 950 °C), (In1, 9Mn0, 1)2Ge2O7 (Thortveiti‐type, Cl2, 1000 → 800 °C), mixed phase crystallizing in the Mn2Ge2O7‐structure showing a composition near MnInGe2O7 (Cl2, 1000 → 800 °C), Mn6, 5In0, 5GeO12 (Braunit‐type, Cl2, 1000 → 800 °C), (FexIn1‐x)Ge2O7 (Thortveitit‐type with x = 0…0, 94; Cl2, 840 → 780 °C). Changing the compositions of the starting materials showed no effect on the composition of the deposit except for the system Fe2O3‐In2O3‐GeO2. 相似文献
The sensing response of metal oxides activated with noble metal nanoparticles is significantly influenced by changes to the chemical state of corresponding elements under operating conditions. Here, a PdO/rh-In2O3 consisting of PdO nanoparticles loaded onto rhombohedral In2O3 was studied as a gas sensor for H2 gas (100–40000 ppm in an oxygen-free atmosphere) in the temperature range of 25–450 °C. The phase composition and chemical state of elements were examined by resistance measurements combined with synchrotron-based in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy. As found, PdO/rh-In2O3 undergoes a series of structural and chemical transformations during operation: from PdO to Pd/PdHx and finally to the intermetallic InxPdy phase. The maximal sensing response (RN2/RH2) of ∼5 ⋅ 107 towards 40000 ppm (4 vol %) H2 at 70 °C is correlated with the formation of PdH0.706/Pd. The InxPdy intermetallic compounds formed around 250 °C significantly decrease the sensing response. 相似文献
Investigation of Chemical Transport in the V2O3/VO2 System The suitability of the transport agent HgCl2 for chemical transport experiments (temperature gradient 1 173/1 113 K) in the system V2O3/VO2 has been investigated. For a constant admixture of transport agent it could be observed that the transport rate, starting with V3O5, increases with increasing ratio O/V for the Magnéli-phases VnO2n–1 of this system (n′(V3O5) = 6 mg/d to n′(V9O17) = 20 mg/d), while the values for n′ = 12 mg/d are even for V2O3 and VO2. 相似文献
On the Crystal Structure of In3Mo11O17 and the Physical Properties of Oligomeric Oxomolybdates In3Mo11O17 is characterized by its molybdate framework Mo22O348? belonging to the general series Mo4n+2O6n+4x? (with n = 5). The phase grows in star-like aggregates and crystallizes within the orthorhombic system (a = 988.0(2) pm, b = 951.2(2) pm, c = 3 176.7(4) pm). There are oligomeric clusters built from five trans edge-sharing Mo6 octahedra, surrounded by O atoms over all empty edges according to the Aufbau principle Mo22OOO. In the remaining structural channel one finds an In68+ polycation which is geometrically equivalent with the one of In11Mo40O62. The Mo—O and Mo—Mo distances within the cluster are the same like in In11Mo40O62, too, but there are shorter inter cluster distances (306 pm) in In3Mo11O17. Disorder in the structure may be understood in terms of the presence of constitutional isomers. While the electrical resistivity of PbMo5O8 resembles the one of a strongly disturbed metal (with a local minimum around 120 K), the temperature characteristic of Tl0.8Sn0.6Mo7O11 is typical for a semiconductor. Oxomolybdates with even longer oligomers like In11Mo40O62 and In3Mo11O17 show metallic conductivity. This course corresponds with the sizes of the clusters and their electronic intercoupling which can be estimated from the specific lengths of the inter cluster distances. The effective magnetic moment grows with increasing cluster length from 0.97 μB (PbMo5O8) to 1.40 μB (In11Mo40O62) per cluster (exception: In3Mo11O12), and so does the contribution of the temperature-independent paramagnetism (from 890 to 2191 × 10?6$ \frac{{{\rm emu}}}{{{\rm mol}}} $ per cluster). Thus, a single condensed octahedron carries roughly 440 × 10?6$ \frac{{{\rm emu}}}{{{\rm mol}}} $ as a temperature-independent paramagnetism, similar to the M6X17 halide clusters. In11Mo40O62 shows an interesting change in the temperature dependence of its magnetic suszeptibility. 相似文献