Crystal growth of calcium carbonate in biological simulation was investigated via egg white protein with different volume fractions,during which calcium carbonate was synthesized by calcium chloride an... 相似文献
The green crystals of Ni1.5H[Ni(OH)6W6O18]·12.5H2O and blue crystals of Na4[Ni(OH)6W6O18]·16H2O were isolated from the acidified (to Z = ν(H+)/ν(WO42−) = 1.00) solutions of Ni(NO3)2-Na2WO4-HNO3-H2O systems. The synthesized salts were identified by chemical analysis, XRPA, and IR spectroscopy. It was shown that the heteropolyanions
belonged to the Anderson-Evans type of structure. An X-ray diffraction study of Na4[Ni(OH)6W6O18]·16H2O was carried out (Mr = 1932.07, triclinic, space group P-1, a = 8.0089(11) ?, b = 10.5758(14) ?, c = 12.1987(16) ?; α = 69.268(13)°, β = 71.069(12)°, γ = 83.816(11)°; V = 914.0(2) ?3 at T = 293 K, Z = 1, ρcal = 3.510 g/cm3, F000 = 874, μ = 19.470 mm−1, −16 ≤ h ≤ 16, −21 ≤ k ≤ 21, −24 ≤ l ≤ 24; the final R factors are RF = 0.0277, wR2 = 0.0469 for the observed reflections (RF = 0.0606, wR2 = 0.0523 for all independent reflections); S = 0.953; CSD-419883). The structure was solved by direct methods and refined in an anisotropic approximation. Hydrogen atoms
were found in a difference synthesis and refined in an isotropic approximation with geometrical limitations. The nature of
water in Na4[Ni(OH)6W6O18]·16H2O was characterized by DTA. XRPA was used to identify the thermolysis products of heteropoly compounds.
Original Russian Text Copyright ? 2009 by G. M. Rozantsev, S. V. Radio, N. I. Gumerova, V. N. Baumer, and O. B. Shishkin
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 311–319, March–April, 2009. 相似文献
Abstract The unique diffusion mechanism in the novel polyatomic anion conductor scandium tungstate is studied by molecular dynamics
simulations of systems with artificially induced WO42− defects and compared to our previous simulations of defect-free structure models. The diffusion activation energy obtained
from structures with built-in defects is smaller than for the defect-free models and in the case of tungstate vacancies close
to the experimental value, suggesting that extrinsic tungstate vacancies due to the volatility of WO3 are important for the experimental conductivity. The validity of the force field used for the molecular dynamics simulations
is further verified by investigating the orthorhombic to monoclinic phase transition of Sc2(WO4)3 under compression. The lattice compressibility in both phases and the phase transition is qualitatively reproduced, though
the simulated phase transition pressure occurred is about 0.55 GPa higher than the experimental one.
Graphical abstract
相似文献
A new page in the phase book : The metastable nitride β‐Ca3N2, the synthesis, crystal structure (see picture), and physical properties of which are reported, is an isotype of corundum (α‐Al2O3). Vacancies in the crystal structure of β‐Ca3N2 are discussed by using full‐potential local orbital methods and taking into account both the physical properties and the density of states.
Triangular luminescent box : Self‐assembly of a new multidentate receptor with europium cations results in the formation of trinuclear discrete complexes. X‐ray crystallography shows that nine‐coordinate cations are linked by ligands to provide a triangular complex in the solid state and in solution. Despite the coordinated solvent molecules, this topologically unusual complex exhibits remarkable luminescent properties.
