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The crystal structures of PrPO4 and NdPO4 have been determined by single crystal X-ray diffraction techniques. The structures are isostructural with CePO4 and LaPO4, and are monoclinic in space group . The cell constants are a = 6.741(3), b = 6.961(4), c = 6.416(3) Å, and β = 103.63(3)° for PrPO4 and a = 6.722(1), b = 6.933(1), c = 6.390(2) Å, and β = 103.72(2)° for NdPO4. The least-squares structural refinements of PrPO4 and NdPO4 yielded R values of 0.034 and 0.038 based on 810 and 947 unique reflections, respectively. The lanthanide metal atoms are coordinated with nine oxygens and are linked together by very slightly distorted tetrahedral phosphate groups. The nine oxygen atoms ligating the lanthanide atoms form a polyhedron that is best described as a pentagonal interpenetrating tetrahedron. 相似文献
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Donald F. Mullica T. Gordon Scott J. Matt Farmer Jason A. Kautz 《Journal of chemical crystallography》1999,29(7):845-848
Adamantan-1-ammonium 1-adamantanecarboxylate, C21H33NO2 (I) is a novel dispiro-type compound. Aminoadamantane derivatives, in which the spiro carbon atoms are part of heterocyclic rings, are of potential interest as biological active substances and antiviral agents. Complex (I) crystallizes in the centrosymmetric space group C2/c (No. 15) with eight molecules in the unit cell with a = 25.227(4), b = 6.527(1), c = 22.489(4) Å, and = 90.75(1)°. The two spiro units are a 1-adamantylammonium cation and a 1-adamantane carbonyloxy anion. The complex units are stabilized by a network of intermolecular carbonyloxy-to-amine hydrogen bonding and van der Waals cohesive forces. Germane bond lengths are: C—N = 1.479(9) and C—O (mean) = 1.25(2) Å. 相似文献
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Jason A. Kautz Donald F. Mullica J. Matt Farmer 《Journal of chemical crystallography》1999,29(6):729-733
The structural analysis of [(n-C4H9)4N]3[Y(NCS)6] (I) using single-crystal diffraction data and full-matrix least squares refinement has been carried out. The hexaisothiocyanate complex crystallizes in the centrosymmetric triclinic space group P
(No. 2) with unit cell constants of a = 12.431(1), b = 12.866(1), c = 22.750(2) Å, = 90.78(1), = 92.05(1), = 96.67(1)°, and Z = 2. The molecular unit consists of three separate cationic tetra-n-butylammonium groups and an independent hexakisisothiocyanatoyttrate anionic group in which the six thiocyanate ligands are octahedrally coordinated through the N atom to the Y central ion. Selected bond distances and angles are presented as well as the synthesis and peripheral studies of (I). 相似文献
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The O ls photoelectron spectra of Ln(OH)3 (Ln = La, Nd, Sm and Gd) can be approximated by the convolution of a core hole spectral density function and a response function which is related to the phonon broadening and instrumental broadening effects. A non-linear least-squares analysis on the convolution integral indicates that the lifetime of the O ls (in the energy domain) is strongly broadened by the phonon excitations. The FWHM (full width at half maximum) of the phonon excitations range from 1.3 to 2.6 eV. 相似文献
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K. Tatsumi M. Tsutsui G.W. Beall D.F. Mullica W.O. Milligan 《Journal of Electron Spectroscopy and Related Phenomena》1979,16(1):113-118
Using the direct CI method perturbation corrections to the Koopmans ionization energies have been obtained up to order 10 for the molecules CN? and H2O. The results are compared with those from the fully converged CI and Bk-type calculations. The convergence of the perturbation series is found to be quite slow although substantial improvement is possible using a variation-perturbation method. 相似文献