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Showing papers on "Orthorhombic crystal system published in 1985"


Journal ArticleDOI
TL;DR: TREOR as discussed by the authors is an indexing program based on trial-and-error methods that contains separate routines for cubic, tetragonal, hexagonal, orthorhombic, monoclinic and triclinic symmetries.
Abstract: An indexing program, TREOR, mainly based on trial-and-error methods is described. The program contains separate routines for cubic, tetragonal, hexagonal, orthorhombic, monoclinic and triclinic symmetries. Ten years usage has been analysed to improve the original program. For monoclinic indexing a specific short-axis test has been developed. The over-all success rate of the program has been found to be better than 90%, and considerably more for orthorhombic and higher symmetries.

1,645 citations


Journal ArticleDOI
J.L. Schlenker1, W.J. Rohrbaugh1, P. Chu1, Ernest W. Valyocsik1, George T. Kokotailo1 
01 Nov 1985-Zeolites
TL;DR: In this article, a disordered structure consisting of ferrierite sheets linked via bridging oxygens located on mirror planes is proposed for this material, characterized by ten-ring noninterpenetrating linear channels whose ideal dimensions are 5.3 × 5.6 A.

115 citations


Journal ArticleDOI
TL;DR: In this paper, the authors report measurements on the lattice parameter, electrical resistivity, thermal conductivity, thermoelectric power, susceptibility, magnetisation and specific heat as well as preliminary neutron diffraction results for the orthorhombic compound CeCu2.
Abstract: The authors report measurements on the lattice parameter, electrical resistivity, thermal conductivity, thermoelectric power, susceptibility, magnetisation and specific heat as well as preliminary neutron diffraction results for the orthorhombic compound CeCu2. The Ce valence is close to three and the overall crystal-field splitting seems to be approximately=200K. CeCu2 behaves as a Kondo lattice system with a 'Kondo temperature' in the crystal-field ground state being of the order of 10-20K. Below 3.5K CeCu2 shows magnetic order of an anisotropic antiferromagnetic type.

92 citations



Journal ArticleDOI
TL;DR: In this paper, the crystal structure of a ternary compound, whose chemical composition is Nd5Fe18B18, has been determined, and the whole structure is now described in the Pccn orthorhombic space group (a=b=7.117A ; c = 35.07A).

80 citations


Journal ArticleDOI
TL;DR: In this article, an oxygen-defect perovskite was isolated by reduction of SrMnO 3−x pervskites in the presence of zirconium and its structure was determined by X-ray powder diffraction and HREM.

80 citations


Journal ArticleDOI
TL;DR: In this article, the formation of solvates of cis(NH3)2PtCl2 and cis-(NH3 2PtI2) with formamide, FA, and substituted formamides has been studied.

76 citations


Journal ArticleDOI
TL;DR: The crystal structures and absolute configurations of three cis-dinitro derivatives of Co(III) have been determined by single crystal X-ray diffraction data collected with a computer-controlled diffractometer as discussed by the authors.

75 citations


Journal ArticleDOI
TL;DR: In this article, a spiral magnetic structure with propagation vector τ = 0.228 × 2πa∗ is found at room temperature and an abrupt change in intensity of the satellite reflections with no change in the propagation vector is attributed to the formation of a double spiral structure.

74 citations


Journal ArticleDOI
TL;DR: In this article, the structural and thermoelastic properties of orthorhombic (Pbnm) MgSiO3 perovskite as a function of temperature and pressure were investigated.
Abstract: We present results of an ab initio study of the structural and thermoelastic properties of orthorhombic (Pbnm) MgSiO3 perovskite as a function of temperature and pressure. Self-consistent free energies are computed using quasiharmonic lattice dynamics with interatomic potentials derived from an electron-gas formulation. At high temperatures the orthorhombic phase undergoes successive second-order transitions to tetragonal and cubic phases. The transition temperatures increase with pressure such that the orthorhombic phase is stable throughout most of the lower mantle although the higher symmetry phases could occur near the top of the lower mantle. At zero pressure the calculated bulk modulus and thermal expansion are in excellent agreement with the available data. We find that for high-temperature isotherms, a finite-strain decompression of the high-pressure equation of state of perovskite substantially overestimates its zero-pressure density and bulk modulus; hence, constraints on the chemical composition of the lower mantle, based on a comparison of the decompressed seismological properties with zero-pressure laboratory data may significantly overestimate the proportion of perovskite in the lower mantle.

73 citations


Journal ArticleDOI
TL;DR: In this paper, a ternary eutectic has been used to sinter Si2N2O ceramics to nearly the theoretical density without the application of pressure.

Journal ArticleDOI
01 Nov 1985-Zeolites
TL;DR: ZSM-23 as discussed by the authors is a high-silica zeolite with lattice parameters of: a = 5.01 ± 0.02A, b = 21.52± 0.04A, and c = 11.13 ± 1.03A.

Journal ArticleDOI
TL;DR: In this article, a perovskite-type phase Sc3AlN1 − x (a = 0.4396-0.4435 nm) occurs at 1273 K. This phase is in equilibrium with ScN, Sc(solid solution), Sc2Al and ScAl.
Abstract: In the ternary ScAlN system a perovskite-type phase Sc3AlN1 − x (a = 0.4396–0.4435 nm) occurs at 1273 K. This phase is in equilibrium with ScN, Sc(solid solution), Sc2Al and ScAl. AlN does not coexist with scandium but does so with ScN, ScAl2 and ScAl3. The binary phase ScAl was found to be orthorhombic with a = 0.502 99 nm, b = 0.989 45 nm and c = 0.312 63 nm. In the Y-Al-N system no ternary phase was found. AlN reacts with up to 40 at.% Y to yield YN and YAl2. Isothermal sections at 1273 K are presented for both ternary systems.

Journal ArticleDOI
TL;DR: In this paper, the van der Waals interactions between lone-pair orbitals on Pb atoms separated by 3.19 A in the (100) direction, and corrugated parallel to (001) were used to stabilize the puckered geometry of the sheets.
Abstract: M r = 223.19, orthorhombic, Pbcm , a = 5.8931 (1), b = 5. 4904 (1), c = 4.7528 (1) A, V = 153.78 (1) A 3 , Z = 4, D x = 9.640 g cm -3 , lambda = 1.893 A, mu = 0. 210 cm -1 , F(000) = 608 fm 2 , T = 295 K, R wp = 0.0846 for 2623 step intensities, R B = 0.0182 for 98 reflections. The structure consists of sheets 2.71 A thick, separated by 3.19 A in the (100) direction, and corrugated parallel to (001). The Pb atoms are located on the surface of these layers, differing little from their positions in metallic Pb, but square-pyramidally bonded to four O atoms in the interior of the layers. The O atoms are in distorted tetrahedral coordination by Pb. The sheets are bonded together solely by van der Waals interactions between lone-pair orbitals on Pb atoms separated by 3.977 (2) and 4. 206 (1) A across the interlayer gap. The puckered geometry of the sheets is stabilized by similar lone-pair interactions between Pb atoms separated by 3.728 (2) A across the corrugations.


Journal ArticleDOI
TL;DR: The crystal structures of three crystalline forms of 4-amino-N-pyridinylbenzenesulfonamide (sulfapyridine) have been determined by X-ray single crystal structure analysis and the powder patterns are computer generated to provide standard diffraction patterns for comparison with the variety of polymorphic forms reported in the literature.

Journal ArticleDOI
TL;DR: The B800-850 light-harvesting complex of Rhodopseudomonas capsulata was crystallized in the presence of detergents as mentioned in this paper, and the crystals were obtained by a vapour diffusion technique, using polyethylene glycol as a precipitant.

Journal ArticleDOI
TL;DR: The phase diagram for the system DIPPC--dipalmitoyl-PC (DIPPC-DPPC) shows that the gel phases formed by either lipid can accommodate only limited amounts of the other species and suggests that the low-temperature orthorhombic phase of DIP PC is distinct in its structure from the "subgel" phase of DPPC.
Abstract: Diisopalmitoylphosphatidylcholine (DIPPC), -phosphatidylethanolamine (DIPPE), and -phosphatidylglycerol (DIPPG) have been synthesized, and the structures of aqueous dispersions of these lipids have been examined by high-sensitivity differential scanning calorimetry, 31P nuclear magnetic resonance, and Raman spectroscopy. DIPPC at temperatures below 23.1 degrees C readily forms a gel phase with the acyl chains packed in an orthorhombic subcell. Above this temperature, this "orthorhombic" phase converts directly to the liquid-crystalline phase. The phase diagram for the system DIPPC--dipalmitoyl-PC (DIPPC-DPPC) shows that the gel phases formed by either lipid can accommodate only limited amounts of the other species and suggests that the low-temperature orthorhombic phase of DIPPC is distinct in its structure from the "subgel" phase of DPPC. DIPPE forms a well-ordered gel phase only in samples that are equilibrated at low temperatures for long times (approximately days to weeks) or at very high lipid concentrations. However, this lipid readily forms an "intermediate" phase with a very disordered acyl chain packing upon cooling from the liquid-crystalline state. Mixtures of DIPPE with DIPPG exhibit similar thermotropic properties. Hydrated DIPPE appears to be stable in the lamellar phase up to at least 98 degrees C, while di-cis- and di-trans-9-hexadecenoyl-PE convert to the hexagonal II phase at 43.5 and 92.5 degrees C, respectively. We discuss the relevance of these results to the structure and stability of bacterial membranes containing branched-chain acyl lipids.

Journal ArticleDOI
TL;DR: In this article, single-crystals of the isotypic compounds PbBiO2X, X  I, Br, and Cl, were prepared by sublimation of pre-reacted micro-crystalline material in the temperature region 670/640°C.

Journal ArticleDOI
TL;DR: The title complex of ZnCl2(C5H9NO2)2, F.W.55, was prepared at pH 4.0 by X-ray diffraction.
Abstract: The title complex was prepared at pH 4.0. The crystal and molecular structures have been determined by X-ray diffraction. The crystals of ZnCl2(C5H9NO2)2, F.W.=366.55, were orthorhombic: space group P212121, a=13.527(3), b=16.263(3), c=6.598(1) A, U=1451.4(5) A3, Z=4, Dm=1.67 g cm−3, Dx=1.68 g cm−3, and μ(Mo Kα)=21.2 cm−1. The zinc atom is coordinated in a tetrahedral geometry to two chlorine atoms and the two carboxyl oxygen atoms of two L-proline ligands. Each L-proline is coordinated as a monodentate ligand.

Journal ArticleDOI
TL;DR: In this article, a new synthetic route to the orthorhombic form of CfBr/sub 3/ was reported, where a few micrograms of monoclinic CfBr was loaded and studied in a triangular-shaped diamond anvil pressure cell similar to that reported by Merrill and Bassett.
Abstract: A new synthetic route to the orthorhombic form of CfBr/sub 3/ is reported. A few micrograms of monoclinic CfBr/sub 3/ is loaded and studied in a triangular-shaped diamond anvil pressure cell similar to that reported by Merrill and Bassett. Based on analysis of the absorption spectra obtained from the CfBr/sub 3/ sample at several pressures up to 3.4 GPa, it is concluded that the structural transformation of monoclinic CfBr/sub 3/ to orthorhombic CfBr/sub 3/ takes place between 1.7 and 3.4 GPa. 10 references, 1 figure.

Journal ArticleDOI
TL;DR: In this paper, the crystal structure of methyl-α-maltotrioside tetrahydrate C 16 H 34 O 16, 4H 2 O has been established by direct methods from 2269 independent reflections and refined to a final R value of 0.054.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the 13C chemical shift of the trans-zigzag inner methylene carbons of cyclic paraffins with the orthorhombic form appears at about 1 ppm further upfield than that with the triclinic form.

Journal ArticleDOI
TL;DR: In this paper, a complex of neutral metal carbonyl clusters was characterized by X-ray crystallography as Bi 2 Fe 3 (CO) 9, which can be extracted into petroleum ether.

Journal ArticleDOI
TL;DR: In this paper, the existence of three main crystalline phases (called III, II and I) in (C12H25NH3)2CdCl4 has been revealed by differential scanning calorimetry.

Journal Article
TL;DR: An X-ray structure analysis has been carried out of the monoclinic variety of the zeolite ferrierite from Altoona, Washington as discussed by the authors, which is typically diamond shaped with (100), (201) and dominant (010) faces.
Abstract: An X-ray structure analysis has been carried out of the monoclinic variety of the zeolite ferrierite from Altoona, Washington. Crystals of this uncommon variety of ferrierite are typically diamond shaped with (100), (201) and dominant (010) faces. The crystal data are a = 18.886(9), b = 14.182(6), C = 7.470(5)A, P = 90.0(1)",space group P2dn, and an approximate unit cell content of Na3KMgo.sMgo.sAlsSi310n' 18H20. The crystal structure was determined by direct phasing of the systematically weak b-reflections (h + k + I = 2n + 1) which are absent in the orthorhombic structure of ordinary ferrierite (space group Immm). Anisotropic refinement converged to R = 0.079 (1164 observed reflections). The monoclinic structure differs from that of the more abundant orthorhombic ferrierite by some changes in the conformation of the framework. This difference may be related to the Mg content.

Journal Article
TL;DR: In this paper, a new synthetic route to the orthorhombic form of CfBr/sub 3/ was reported, where a few micrograms of monoclinic CfBr was loaded and studied in a triangular-shaped diamond anvil pressure cell similar to that reported by Merrill and Bassett.
Abstract: A new synthetic route to the orthorhombic form of CfBr/sub 3/ is reported. A few micrograms of monoclinic CfBr/sub 3/ is loaded and studied in a triangular-shaped diamond anvil pressure cell similar to that reported by Merrill and Bassett. Based on analysis of the absorption spectra obtained from the CfBr/sub 3/ sample at several pressures up to 3.4 GPa, it is concluded that the structural transformation of monoclinic CfBr/sub 3/ to orthorhombic CfBr/sub 3/ takes place between 1.7 and 3.4 GPa. 10 references, 1 figure.

Journal ArticleDOI
TL;DR: In this paper, temperature dependences of the elastic constants of the Kondo lattice substance CeCu 6 have been measured by the ultrasonic method, which is associated with the structural phase transition from the orthorhombic D 16 2h to the monoclinic C 5 2h structures at T c =168 K.
Abstract: Temperature dependences of the elastic constants of the Kondo lattice substance CeCu 6 have been measured by the ultrasonic method. The transverse C 66 mode exhibits a complete softening, which is associated with the structural phase transition from the orthorhombic D 16 2h to the monoclinic C 5 2h structures at T c =168 K. The crystalline electric field effect has been observed in the softening of the elastic constants below about 100 K. The longitudinal C 11 and C 33 modes show a remarkable softening below 10 K, which is related to the excitation of the Kondo lattice.

Journal ArticleDOI
TL;DR: The structure of Cs2Na[MoO(CN)4(N3)] was determined by single-crystal X-ray diffraction methods from diffractometer data and refined to R = 0.051 as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the crystal structures of a subclass of compounds of the type [Cu(CN)Ln] have been determined by recrystallization of copper(I) cyanide from (or with) the parent base.
Abstract: Compounds of the type [Cu(CN)Ln][L = diethylamine, (1), triethylamine, (2), 4-methylpyridine, (3), or 1,10-phenanthroline, (4)] have been synthesized by recrystallization of copper(I) cyanide from (or with) the parent base and their crystal structures have been determined by single-crystal X-ray diffraction methods; n= 1 except in the case of (3) where n= 1.5. Crystals of (1) are monoclinic, space group P21/n, with a= 15.108(7), b= 7.321(5), c= 13.699(6)A, β= 103.00(4)°, and Z= 8; R was 0.044 for No= 871 independent ‘observed’ reflections. For (2), crystals are orthorhombic, space group Pnma, with a= 9.501(4), b= 8.921(4), c= 11.279(5)A, and Z= 4; R= 0.039, No= 369. For (3), crystals are monoclinic, space group Cc, with a= 9.587(3), b= 16.326(4), c= 14.022(4)A, β= 109.38(2)°, and Z= 4; R= 0.031, No= 1 070. For (4), crystals are trigonal, space group P31, with a= 9.175(5), c= 11.753(8)A, and Z= 3; R= 0.041, No= 812. All complexes are one-dimensional polymers, that in (2) being disposed completely in a mirror plane except for the substituent alkyl groups. Copper atoms in (1) and (2) are trigonally planar co-ordinated by C,N(cyanide) and N(base), as is one of the two copper atoms in (3); the other copper atom in (3) is unusual, being four-co-ordinated pseudo-tetrahedrally by C,N(cyanide) and two N(base). A similar copper environment is found in (4).