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Wolfgang Leib Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1988,119(2):157-164
Solid state reactions, by using a flux, lead to the new compounds Sr3Ga2O5Cl2 (A) and Sr3Fe1.18Al0.82O5Cl2 (B). By means of single crystal X-Ray determinations a monoclinic symmetry (space group C
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-P21, (A):a=9.569 (2) Å; (B):a=9.550 (2) Å,Z=4) was found. Both compounds are not isotypic to Sr3Fe2O5Cl2 but crystallize like Ba3Fe2O5Cl2. 相似文献
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A new family of salt-containing, mixed-metal silicates (CU-14), Ba6Mn4Si12O34Cl3 (1) and Ba6Fe5Si11O34Cl3 (2), was synthesized via the BaCl2 salt-inclusion reaction. These compounds crystallize in the noncentrosymmetric (NCS) space group Pmc2(1) (No. 26), adopting 1 of the 10 NCS polar, nonchiral crystal classes, mm2 (C2v). The cell dimensions are a = 6.821(1) A, b = 9.620(2) A, c = 13.172(3) A, and V = 864.4(3) A3 for 1 and a = 6.878(1) A, b = 9.664(2) A, c = 13.098(3) A, and V = 870.6(3) A3 for 2. The structures form a composite framework made of the (M(4+x)Si(12-x)O34)9- (M = Mn, x = 0; M = Fe, x = 1) covalent oxide and (Ba6Cl3)9+ ionic chloride sublattices. The covalent framework exhibits a pseudo-one-dimensional channel where the extended barium chloride lattice (Ba3Cl1.5)(infinity) resides, and it consists of fused eight-membered meta-silicate rings propagating along [100] via sharing two opposite [Si2O7]6- units to form an acentric lattice. Single-crystal structure studies also reveal the ClBa4 unit adopting an interesting seesaw configuration, in which the lone pair electrons of chlorine preferentially face the oxide anions of the transition metal silicate channel, thus forming the observed polar frameworks. Similar to the synthesis of organic-inorganic hybrid materials, the salt-inclusion method facilitates a promising approach for the directed synthesis of special framework solids, including NCS compounds, via composite lattices. 相似文献
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Horst P. Beck Manfred Schramm Robert Haberkorn Robert Dinnebier Peter W. Stephens 《无机化学与普通化学杂志》1998,624(3):393-398
The synthesis of a hitherto unknown 6 : 5 phase in the quasi-binary system RbCl/PbCl2 and its structure determination is reported. The compound Rb6Pb5Cl16 crystallizes in the tetragonal space group P4/mbm with a large variety of different coordination polyhedra for the cations. Special feature of the structure is a statistical distribution of Rb and Pb at one of the cation sites with a ratio of 1 : 3 as defined by electroneutrality. There is no evidence for symmetry reduction by ordering. 相似文献
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Cu3AlCl6 and Cu2Al2Cl8, Gas Complexes in the System CuCl/Al2Cl6 Investigations by mass spectroscopy in the system CuCls/Al2Cl6,gestablished that only Cu3AlCl6 and Cu2Al2Cl8 are observed as principal gas complexes. Results of flow measurements published by LAUGHLIN and Gregory (1976) which were attributed erroneously by these authors to the complex CuAlCl4 may be described by the equilibria given in “Inhaltsübersicht”. The complexes cu3AlCl6 and Cu2Al2Cl8 are supposed to have a cube type structure similar to Cu4Cl4. 相似文献
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Mass Spectroscopic Observations and Chemical Transport Experiments with the Systems VCl3/Al2Cl6 and VCl2/Al2Cl6 By mass spectrometry the equilibrium VCl3,s + 0.5 Al2Cl6,g ? VAlCl6,g has been determined: ΔH°(298) = 25.6(±0.5) kcal; ΔS°(298) = 23.0(±3) cal/K, ΔCp (assumed) = ?4 cal/K. This is approximately in agreement with results determined by ligand field spectroscopy by ANUNDSKÅS and ØYE (A. and Ø.). For the dimerization of VCl3,g values for ΔH and ΔS have been derived. The molecule VAl2Cl9 assumed by A. and Ø. could not been observed by mass spectrometry. For the VCl2/Al2Cl6 complex, observed by chemical transport, A. and Ø. give the formula VAl3Cl11. This molecule could not been observed by mass spectrometry. This suggests a smaller concentration, compared with the results of A. and Ø. Stabilization of VCl2,s (by metal-nietal-bonds) shifts the reaction to the left, whith explains the lower complex concentration as well as the larger molecular weight of the complex. With chlorides stabilized by stronger metal-metal bonds (MoCl3, MoCl2, Nb3Cl8) AlCl3 complexes are not formed in observable concentrations. The chemical transport of VCl2 with Al2Cl6 needs relatively high temperatures (973 → 873 K). In this case the addition of SiCl4 hinders the attack of the quartz ampoule by Al2Cl6. Using a VCl3 + VCl2 mixture, VCl3 is transported by Al2Cl6 (673 → 623 K) into the colder region. If afterwords the ampoule is reversed, VCl3 again moves into the colder region, but the thermal decomposition of VCl3 at the same time causes that a VCl2-residue remains in the hot region. 相似文献
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Tb3+ ions were incorporated in P-Si matrix material through a sol-gel process. Luminescence properties of Tb3+ as a function of dopant, firing temperature, composition and structure of matrices were investigated. The gels synthesized by the reaction of P2O5 or H3PO4 with tetraethoxy silane and TbCl3 as dopant were fired in air from the temperature 25~1000℃ to form P-Si crystalline phase. The crystal structure was determined by powder X-ray diffraction. Si5O(PO4)6 were the only crystalline phase and belong to hexagonal crystal system. The emission of 5D4-7F5(~545nm) transition of Tb3+ in the P-Si system is composed of two peaks. The amount of doping Tb3+ varied from 0.664% to 1.644%, and no obvious concentration quenching was observed in this doping concentra-tion range. The intensity of Tb3+ emission increased with firing temperature increasing and becomes stable at 800~1000℃. 相似文献