Showing papers on "Isostructural published in 1971"
TL;DR: In this article, single crystals and polycrystalline samples of the disulfides, diselenides, and ditellurides of technetium and rhenium have been prepared and studied.
Abstract: Single crystals and polycrystalline samples of the disulfides, diselenides, and ditellurides of technetium and rhenium have been prepared and studied. All these compounds except ReTe2 have layer structures. ReS2 is triclinic and isostructural with ReSe2, the structure of which is completely known. TcS2 and TcSe2 are also triclinic; their structure differs from that of the rhenium compounds but is probably related to it. TcTe2 has a monoclinic structure, while ReTe2 is orthorhombic. The optical band gaps of the sulfides and selenides which are essentially diamagnetic semiconductors, have been determined. The thermal decomposition of Re2S7 is described.
163 citations
69 citations
TL;DR: In this paper, the Raman spectra of calcite, CaCO3 II, and Ca CO3 III have been studied at various pressures as high as 40 kbar and 13 lines have been observed in the previously unreported spectrum of CaCO 3 II and 20 lines are reported for the Ca CO 3 III spectrum.
Abstract: Raman spectra of calcite, CaCO3 II, and CaCO3 III have been studied at various pressures as high as 40 kbar. Thirteen lines have been observed in the previously unreported spectrum of CaCO3 II and 20 lines are reported for the CaCO3 III spectrum. These spectra are compared with Raman spectra of aragonite, KNO3 III, and KNO3 IV; and previous suggestions that CaCO3 II and KNO3 III may be isostructural and that CaCO3 III and KNO3 IV also may be isostructural are shown to be incorrect. Alternative structures for CaCO3 II and CaCO3 III are briefly considered.
60 citations
48 citations
TL;DR: Hexakis(trimethylsilylmethyl)dimolybdenum has a short Mo-Mo bond (2 167 A) corresponding to a triple bond; similar neopentyl and benzyl derivatives and the isostructural tungsten compound are reported as discussed by the authors.
Abstract: Hexakis(trimethylsilylmethyl)dimolybdenum has a short Mo–Mo bond (2 167 A) corresponding to a triple bond; similar neopentyl and benzyl derivatives and the isostructural tungsten compound are reported.
39 citations
TL;DR: The structure of Ph4Si was refined to R 0·073 for 413 independent reflections as discussed by the authors, and the mean bond lengths (not corrected for libration) were: Si−C 1·383, C−H 1·00 A.
Abstract: Crystals of Ph4Si are tetragonal, space group P21c,a= 11·46(1), c= 7·09(3)A, Z= 2, and are isostructural with Ph4Sn. The molecule possesses exact (S4) symmetry. The mean bond lengths (not corrected for libration) are: Si–C 1·383, C–H 1·00 A. There is a significant deviation from local hexagonal symmetry of the phenyl group, involving a small displacement of the carbon atom attached to silicon. The structure was refined to R 0·073 for 413 independent reflections.
34 citations
TL;DR: In this paper, the role of the metal in the reversible addition of small molecules to isostructural d8 complexes of rhodium and iridium was assessed in terms of acid-base reactions.
32 citations
TL;DR: The crystal structure of CaCrF 5 has been determined by X-ray single crystal analysis as discussed by the authors, which is made up of zigzag chains formed by the (CrF 6 ) 3− octahedra sharing common corners.
29 citations
TL;DR: The photoelectron spectra of C2(NMe2)4 and {C[N(Me)CH2]2}2 each show five bands below 10·5 eV with the first vertical ionisation potential at 5·95 or 6·06 eV, as is consistent with their strong reducing properties; these bands are assigned as π levels of various symmetries on the basis of a simple Huckel calculation as discussed by the authors.
Abstract: The photoelectron (P.E.) spectra of C2(NMe2)4 and {C[N(Me)CH2]2}2 each show five bands below 10·5 eV with the first vertical ionisation potential at 5·95 or 6·06 eV (cf., C2H4, 10·5 eV; Na 5·1 eV), as is consistent with their strong reducing properties; these bands are assigned as π levels of various symmetries on the basis of (i) a good fit for experimental data with a simple Huckel calculation, and (ii) comparison of the spectra of the isostructural molecules C2(NMe2)4 and B2(NMe2)4.
29 citations
TL;DR: In this paper, a high-pressure form of TaOPO4 has been synthesized at 25 to 60 kbar and 500 to 1500° C. It was found to be isostructural with the low-temperature form of NbOPO 4.
28 citations
TL;DR: The crystal structure of Nb3Se4 has been determined and refined by single-crystal X-ray methods as discussed by the authors, and the final unweighted R factor of the hexagonal unit cell (space group P6 3 m, a = 10.007 4 ± 1 5 and c = 3.4667 ± 8 A ) equaled 0.058.
TL;DR: P4Se5 has been isolated from the reaction of bromine with P4Se3 in carbon disulphide, and identified by crystal structure determination as mentioned in this paper, but the crystal structures are not isostructural.
Abstract: P4Se5 has been isolated from the reaction of bromine with P4Se3 in carbon disulphide, and identified by crystal structure determination; the analogous reaction of bromine with P4S3 yields P4S5. The crystals of P4Se5 are orthorhombic, space group Pn21a, a= 12·79(2), b= 11·19(2), c= 6·66(2)A, Z= 4. The refinement of site occupation factors for trial atoms facilitated the structure determination. The molecule has the same unusual cage structure as P4S5, but the crystals are not isostructural.
TL;DR: The MII naphthyl hydrides as discussed by the authors system M0(naphthalene)(dmpe)2⇌ MIIH (naphthsyl)(dmpe), where M = Ru or Os, and dmpe = Me2P·CH2·-CH 2·PMe2, involves an equilibrium between a low-valent M0 complex and a hydridic higher-value structure.
Abstract: The system M0(naphthalene)(dmpe)2⇌ MIIH(naphthyl)(dmpe)2, where M = Ru or Os and dmpe = Me2P·CH2·-CH2·PMe2, involves an equilibrium between a low-valent M0 complex and a hydridic higher-valent structure. The structures of the crystals obtained from this system have been determined for both M = Ru and M = Os showing that, in the solid state, these compounds are MII naphthyl hydrides. The ruthenium and osmium complexes are isostructural (P21/c, Z= 4, a=ca. 15·3, b=ca. 18·7 A, and β=ca. 114°). Diffractometer data have been refined to R= 0·080 and 0·072 (Ru and Os complexes respectively). The metal atom is approximately octahedrally co-ordinated with the hydridic hydrogen cis to the σ-bonded naphthyl group. The Ru–H distance is 1·7 A; the M–P bond lengths range from 2·28 to 2·33 A with the longer bonds trans to hydrogen. The two M–C bonds, Ru–C 2·16 and Os–C 2·13 A, are longer than comparable M–C(aryl) bonds. Both phosphine ligands in each complex have disordered bridging methylene groups. The σ–π rearrangement in the equilibrium system is discussed in relation to the known structures of metal–arene complexes.
TL;DR: The structure of the compound [Ph3MeP]2[Zn(B10H12)2] has been determined by X-ray diffraction analysis; 4569 reflections were measured on a four-circle diffractometer.
Abstract: The structure of the compound [Ph3MeP]2[Zn(B10H12)2] has been determined by X-ray diffraction analysis; 4569 reflections were measured on a four-circle diffractometer. Crystals of the salt are monoclinic, space group C2/c with Z= 8 in the unit cell of dimensions a= 41·549(34), b= 10·071(8), c= 23·500(18)A, and β= 99·20(5)°. The structure was solved by Fourier methods and refined by least-squares calculations to a final R of 8·9%; all 121 atoms were located. The anionic complex can be considered to comprise two bidentate B10H122– ligands co-ordinated tetrahedrally to zinc(II). The distortions in the boron cluster due to the large size of the zinc atom are discussed. The cadmium and mercury analogues were shown to be isostructural.
TL;DR: The crystal and molecular structure of diaquobis(methoxyacetato)nickel(II) has been determined by three-dimensional X-ray methods (R= 0·119).
Abstract: The crystal and molecular structure of diaquobis(methoxyacetato)nickel(II) has been determined by three-dimensional X-ray methods (R= 0·119). The monoclinic unit cell, space group P21/n, has dimensions a= 6·90 ± 0·02, b= 7·15 ± 0·02, c= 10·05 ± 0·03 A, γ= 99·8 ± 0·3°, with Z= 2. The complex is a chelate and isostructural with its copper analogue. The carboxylate ligand dimensions and angles are equal within experimental error and the hydrogen-bond system is equivalent but in the nickel co-ordination octahedron the observed bond lengths are Ni–OMe 1·99, Ni–OH2 2·07, and Ni–OCO 2·05 A. The longer Cu–OMe (2·13 A) contact in the copper complex appears to be due neither to steric hindrance nor to low bonding ability of the ethereal oxygen atom. In tetra-aquobis(phenoxyacetato)nickel(II), the carboxylate ligands are unidentate.
TL;DR: In this paper, a single-crystal X-ray diffraction study showed that β-P4S3I2 is isostructural with P4Se3I 2.
Abstract: Addition of iodine to P4S3 in solution yields a new isomer of the di-iodo-compound, β-P4S3I2. The i.r., Raman, and mass spectra of both isomers are reported. A single-crystal X-ray diffraction study shows that β-P4S3I2 is isostructural with P4Se3I2; the crystals are orthorhombic, space group Pnma, a= 9·45, b= 16·33, c= 6·67 A, Z= 4. The molecular structure is derived from that of P4S3 by the addition of a molecule of iodine across a P–P bond. On melting, β-P4S3I2 undergoes a rapid skeletal rearrangement to give the stable isomer, α-P4S3I2.
TL;DR: The preparation of osmium pentafluoride is described in this paper, where the crystal of the solid is monoclinic, space group P21/c, a= 5·53, b= 9·91, c= 12·59 A, β= 99·5°.
Abstract: The preparation of osmium pentafluoride is described. Crystal of the solid are monoclinic, space group P21/c, a= 5·53, b= 9·91, c= 12·59 A, β= 99·5°. The structure was refined by three-dimensional least-squares methods, the final R being 0·106 for 642 independent reflections. The compound is isostructural with ruthenium pentafluoride. The structural unit is a tetramer with osmium atoms at the corners of a rhombus, non-linearly linked by bridging fluorine atoms. The fluorine atoms have been shown to form an approximately hexagonal closepacked lattice.
TL;DR: In the isostructural compounds CaSrGe 2 O 6, CaBaGe 2O 6 and SrBaGe2O 6, using Pb-activation and Mn-activation, 50% of Si can be substituted for Ge without any decrease in the quantum efficiency of the phosphor as discussed by the authors.
TL;DR: In this paper, the electron paramagnetic resonance of Mn2+ has been studied in single crystals of magnesium sulfate heptahydrate (MgSO4 · 7 H2O) at 300°K.
Abstract: Electron paramagnetic resonance of Mn2+ has been studied in single crystals of magnesium sulfate heptahydrate (MgSO4 · 7 H2O) at 300°K. Mn2+ was found to substitute for Mg2+ and exhibit four inequivalent magnetic complexes corresponding to the tetramolecular unit cell of MgSO4 · 7 H2O. The results are compared with those for Mn2+ in isostructural NiSO4 · 7 H2O. The observed differences in the EPR of Mn2+ in crystals of the two salts are attributed to the magnetic interaction of Ni2+ and Mn2+.
TL;DR: In this paper, the origin of the 19F NMR chemical shift increase in metal fluorides with cation d10- and f14-configurations as compared to isostructural fluorides having a p6- configuration was examined.
01 Jan 1971
TL;DR: In this article, X-ray counter data for the dihydrogen hexafluorosilicate monohydrates ofp-bromoaniline, BrC6H4NH2.1/2H2SiF6.
Abstract: Analysis of X-ray counter data for the dihydrogen hexafluorosilicate monohydrates ofp-bromoaniline, BrC6H4NH2.1/2H2SiF6.H2O, andp-toluidine, CH3C6H4NH2.1/2H2SiF6.H2O, has shown that the two compounds are isostructural and that the orthorhombic crystals belong to the space groupPbca, witha = 7·80,b = 24·45,c = 9·48 A anda = 7·89,b = 23·87,c = 9·53 A, respectively, there being eight molecules in each unitcell. Structure analysis was initiated by the heavy atom method, and subsequent difference syntheses, carried out on thep-bromoaniline compound, then on thep-toluidine analogue, revealed the entire structure apart from the hydrogen atoms. From a difference synthesis on data for thep-toluidine compound refined by full-matrix least-squares procedures, the hydrogen atom sites were located, a reliability index,R = 0·052, being attained. The structures are sheet-like with bi-polar grouping of amino groups on either side of sheets of SiF
6
2−
groups and are cross-linked by ionic forces and hydrogen bonds. The SiF
6
2−
ion is octahedral, with an average Si-F distance of 1·69 ± 0·02 A.
TL;DR: In this article, it was shown that tin(IV) oxide (SnO2) has been formed in a krypton matrix by reaction of the elements; isotopic splitting in the i.r.r spectrum suggests that it is isostructural with carbon dioxide.
Abstract: Molecular tin(IV) oxide (SnO2) has been formed in a krypton matrix by reaction of the elements; isotopic splitting in the i.r. spectrum suggests that it is isostructural with carbon dioxide.
01 Apr 1971
TL;DR: Rubidium and ammonium hydrogen glutarates (M+−CO2.C3H6.CO2H) each crystallize with four molecules in orthorhombic unit cells of almost identical dimensions as mentioned in this paper.
Abstract: Rubidium and ammonium hydrogen glutarates (M+−CO2.C3H6.CO2H) each crystallize with four molecules in orthorhombic unit cells of almost identical dimensions: (M = Rb)a = 18·55,b = 7·57,c = 5·29 A; (M = NH4)a= 18·59,b= 7·56,c= 5· 27 A. They have very similar structures, but they are not isomorphous: space groupsCmma (Rb) andPmaa (NH4).
TL;DR: In this article, it is confirmed from X-ray powder crystallographic measurements that KAgF4(III) is isostructural with KAuF4/4/III and KBrF4 /4/3.
TL;DR: In this article, the temperature dependence of chlorine N.Q. frequencies in isostructural cubic compounds A2MCI6, where M is a metal of the third row transition series, was investigated.
TL;DR: In this article, a powder neutron diffraction measurement was performed on RbCoBr3 and the results indicated that the compound exhibits a transition to an antiferromagnetic phase in which the spins are alternately aligned along c with a (+ + + ) configuration for the three spins in the basal plane.
Abstract: Powder neutron diffraction measurements have been performed on RbCoBr3. The results indicate that at TN = 36 °K, the compound exhibits a transition to an antiferromagnetic phase in which the spins are alternately aligned along c with a (+ + —) configuration for the three spins in the basal plane. This is in contrast to the spiral arrangement previously deduced for the isostructural compounds CsNiCl3 and RbNiCl3. Single crystal measurements in the latter compound are presented that demonstrate that for T > 2.27 TN, the magnetic scattering is essentially confined to planes perpendicular to the c* axis.
TL;DR: The first isostructural HgMoO 4 and HgWO 4 was reported in this paper, having a space group of Cc or C2/c.
TL;DR: The crystal structure parameters for PaBr4 (isostructural with ThCl4) have been determined from quantitative X-ray powder data and refined to R 0·123 as discussed by the authors.
Abstract: The crystal structure parameters for PaBr4(isostructural with ThCl4) have been determined from quantitative X-ray powder data and refined to R 0·123. The Pa–Br bond distances are 2·77 and 3·07 A; a value of 1·63 A is deduced for the covalent single-bond radius of PaIV.