摘要:

AbstractThe infra‐red and Raman spectra of the solid solutions forming in the KNO3–NH4NO3–H2O system have been made. The spectra have been in agreement with the structure of mixed crystals settled previ

ISSN:0232-1300    

DOI:10.1002/crat.2170300309

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe solubility in the Cu(HCOO)2–Sr(HCOO)2–H2O system has been studied by the method of physico‐chemical analysis at 25 and 50 °C. It has been established that two double salts are formed in the system: CuSr2(HCOO)6· H2O at 25 °C and CuSr(HCOO)4· 4 H2O at 50 °C. The latter salt has not yet been described in the literature. It has been characterized by X‐ray powder diffraction and DT and TG analysis. CuSr(HCOO)4· 4 H2O crystallizes in the triclinic system with lattice parametersa= 12.376(6) Å,b= 13.394(4) Å,c= 11.508(6) Å, α = 93.38(3)°, β = 94.01(3)°, γ = 75.04(3)°. Dehydration

ISSN:0232-1300    

DOI:10.1002/crat.2170300310

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170300311

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractSamples with the stoichiometric composition Bi2−xPbxSr2Ca2Cu3−yByOz(x= 0.3,y= 0.2, 0.25, 0.3, 0.4) ceramics were prepared by a solid state reaction method. The samples were annealed at 850 °C for 100 hours (treatment A), and the other at 850 °C for 200 hours (treatment B). From the X‐ray diffraction data of a ceramic sample it is revealed that all the samples were mixed phases of 2212 and 2223. The variation of the lattice parameters with the dopant level are represented. From the D.C. four‐probe electrical resistivity data it was found that for the samples subjected to treatment B theTc(0) values were higher than those with treatment A. The A.C. susceptibility data were collected by change in the inductance method. The effect of boron doping on the phase formation andTc(0) is presented and the volume fraction of the phases estimated from the X‐ray data. The presence of boron in the samples was confirmed by the inductive coupled plasma method. The microstructure of the samples was studied by scanning electron

ISSN:0232-1300    

DOI:10.1002/crat.2170300312

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe title compound has been synthesized and its crystal structure determined at room temperature. MW = 927.86, monoclinic, space group P21/c,Z= 2,a= 9.283(1) Å,b= 16.239(2) Å,c= 12.209(1) Å, β = 99.848(9)°. The crystal structure consists of repeated [Cu2(μ–C2O4)(C10H8N2)2· (H2O)2]2cations and non‐coordinated saccharin anions. Each copper ion is in a square pyrimidal environment with two oxalate oxygen and two bipyridine nitrogen atoms as a base and one water molecule at the apex. The two copper ions are bridged by oxalato and the distance

ISSN:0232-1300    

DOI:10.1002/crat.2170300313

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe crystal structure of R(–)‐1‐tosyl‐2‐methylpyrrolidine has been determined by X‐ray structure analysis. The compound crystallizes in the monoclinic space group P21with cell parametersa= 7.858(1),b= 14.929(6),c= 11.128(1) Å, β = 105.42(1)°. The structure has been solved by direct methods and refined toR= 0.046. There are two crystallographically independent molecules A and B in the asymmetric unit. The pyrrolidine ring of molecule A is disordered with atom C4 occupying two possible sites. The S atom has a distorted tetrahedral coordination in both the molecules. Two bifurcated hydrogen bonds are observed. Molecules are held together by

ISSN:0232-1300    

DOI:10.1002/crat.2170300314

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe diffraction pattern simulation of four YBa2Cu3Oxsingle crystals with inhomogeneous distribution was successfully carried out on the base of the theory of X‐ray diffraction by disordered interstratified structures. The specific feature of their two‐component irregular mixed‐layered structures is the total segregation of layers with various oxygen content that led to the formation of so‐called intergrowth structures. The concentration of admixture layers varied from 10 to 40% while oxygen content difference within the crystal ranged from 0.5 to 0.3. In one of the crystals the fluctutations of layer heights corresponded to oxygen variation from 6.2

ISSN:0232-1300    

DOI:10.1002/crat.2170300315

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe crystal and molecular structure of 1,16‐dibromohexadecane have been determined by X‐ray diffraction. Crystal data; empirical formula, C16H32Br2, formula weightMr= 384.24, monoclinic, P21/a,a= 31.00(2),b= 5.38(1),c= 5.48(1) Å, β = 90.8(2)°,V= 914(3) Å3,Z= 2,Dx= 1.396 g/cm3, δ(CuKα) = 1.5418 Å, μ(CuKα) = 55.41 cm−1,F(000) = 396.00,T= 293 ± 1 K,wR= 0.082,R= 0.054 for 940 unique reflections [I>3.00σ(I)]. The molecular skeleton has an all trans zigzag hydrocarbon chain. The crystal has a layer structure, but the directions of molecular axes in neighbouring layers alternate. This molecular packing resembles to that of 1,16‐hexadecanediol, whereasn‐alkanes or α‐monosubstitutedn‐alkanes do not appreciably have these molecular arrangement. The effect of terminal groups at both ends of α,ω‐disubstitutedn‐alkanes on the

ISSN:0232-1300    

DOI:10.1002/crat.2170300316

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe X‐ray crystal structure analysis of Na‐sulfadimidine is reported. Crystals are triclinic. Space group P1witha= 5.785(2),b= 11.568(1),c= 12.722(2) Å, α = 70.02(1), β = 78.71(2), γ = 77.73(2)° andZ= 2. Crystal structure was solved by direct method to anR‐value of 0.061 for 2441 unique reflections. It is a type of five‐fold coordination complex of Na where Na atom is surrounded by four oxygen atoms and one nitrogen atom: three oxygen atoms and the nitrogen atom belongs to the sulfonyl moiety from three different sulfadimidine molecules and the fourth oxygen atom belongs to solvent water molecule. The crystal structure is stabilized by hydrogen bonds and van der

ISSN:0232-1300    

DOI:10.1002/crat.2170300317

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170300318

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY