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1.
New sodium iron orthophosphate NaFe 4 2+ Fe 3 3+ [PO4]6 was synthesized by the hydrothermal method. The crystal structure (sp. gr. $P\bar 1$ ) was established by the heavy-atom method, with the exact chemical formula of the compound being unknown; R hkl = 0.0492, R whkl = 0.0544, S = 0.52. The new compound is analogous to iron phosphate Fe 3 2+ Fe 4 3+ [PO4]6 studied earlier. However, these two compounds differ in the Fe2+ and Fe3+ contents, because Na+ ions in the new compound are located at the centers of symmetry not occupied earlier. 相似文献
2.
The combinatorial-topological analysis of the structures of framework Li,Ge-germanates of the compositions Li2GeVIGe 2 IV O6(OH)2 (sp. gr. B 2/b), Li2GeVIGe 3 IV O9 (sp. gr.Pcca), Li4Ge 2 VI Ge 7 VI O20 (sp. gr. C2), and Li2GeVIGe 6 IV O15 (sp. gr. Pbcn) has been made with the separation of subpolyhedral structural units (SPSUs) built by octahedra and tetrahedra. The topologically invariant SPSUs are separated in three-dimensional frameworks of the structures. A possible mechanism of the matrix assemblage from the SPSU invariants in crystal structures of the framework Li,Ge-germanates is suggested. 相似文献
3.
A. V. Savchenkov A. V. Vologzhanina V. N. Serezhkin D. V. Pushkin L. B. Serezhkina 《Crystallography Reports》2014,59(2):190-195
Single crystals of UO2(n-C3H7COO)2(H2O)2 (I) and Mg(H2O)6[UO2(n-C3H7COO)3]2 (II) are synthesized. Their IR-spectroscopic and X-ray diffraction studies are performed. Crystals I are monoclinic, a = 9.8124(7) Å, b = 19.2394(14) Å, c = 12.9251(11) Å, β = 122.423(1)°, space group P21/c, Z = 6, and R = 0.0268. Crystals II are cubic, a = 15.6935(6) Å, space group $Pa\bar 3$ , Z = 4, and R = 0.0173. The main structural units of I and II are [UO2(C3H7COO)2(H2O)2] molecules and [UO2(C3H7COO)3]? anionic complexes, respectively, which belong to AB 2 01 M 2 1 (I) and AB 3 01 (II) crystal chemical groups of uranyl complexes (A = UO 2 2+ , B 01 = C3H7COO?, and M 1 = H2O). A crystal chemical analysis of UO2 L 2 · nH2O compounds, where L is a carboxylate ion, is performed. 相似文献
4.
L. B. Serezhkina E. V. Peresypkina N. A. Neklyudova A. V. Virovets V. N. Serezhkin 《Crystallography Reports》2013,58(2):275-279
Compound (CN3H6)2[(UO2)2(C2O4)(CH3COO)4] is synthesized and characterized by IR spectroscopy and single-crystal X-ray diffraction [a = 8.5264(2) Å, b = 13.8438(4) Å, c = 10.7284(2) Å, β = 103.543(1)°, space group P21/n, Z = 2, and R = 0.0258]. The main structural units of the crystals are binuclear [(UO2)2C2O4(CH3COO)4]2? groups, which belong to the A 2 K 02 B 4 01 crystal chemical group of uranyl complexes (A = UO 2 2+ , K 02 = C2O 4 2? , and B 01 = CH3COO?). The coordination polyhedron of the uranium atom is the UO8 hexagonal bipyramid with the oxygen atoms of the uranyl ion at the axial positions. Uranium-containing groups and guanidinium cations are connected by electrostatic interactions and by the hydrogen bond system, which involves hydrogen atoms of guanidinium cations and oxygen atoms of oxalate and acetate anions. The results of the spectroscopic study of the compound agree with the X-ray diffraction data. 相似文献
5.
O. V. Yakubovich I. M. Steele V. S. Rusakov V. S. Urusov 《Crystallography Reports》2006,51(3):401-411
The crystal structure of a synthetic analog of the mineral lipscombite (Fe 2.3 2+ Fe 4.7 3+ )[PO4]4O2.7(OH)1.3 obtained under hydrothermal conditions in the LiF-Fe2O3-(NH4)2HPO4-H2O system is resolved (R = 0.040) by X-ray diffraction analysis (Bruker Smart diffractometer with a highly sensitive CCD detector, MoK α radiation): a = 14.776(3) Å, b = 14.959(3) Å, c = 7.394(1) Å, β = 119.188(4)°, sp. gr. C2/c, Z = 4, ρexp = 3.8 g/cm3, ρcalcd = 3.9 g/cm3. Fe2+ and Fe3+ cations are statistically distributed in each of four crystallographically independent positions, while occupying the corresponding octahedra with probabilities of 60, 90, 100, and 91%. The ratio Fe2+/Fe3+ in the composition of the crystals was established by Mössbauer spectroscopy. Lipscombite is interpreted as a mineral of variable composition described by the formula (Fe x 2+ Fe n?x 3+ )[PO4]4Oy(OH)4?y . The field of stability is determined as a function of the iron content and the ratio Fe2+/Fe3+. It is shown that at n = 6 iron cations are ordered in octahedra and barbosalite structure is formed. An interpretation of genetically and structurally related members of the lipscombite family within a unified polysomatic series is proposed. 相似文献
6.
Hydrogen sulfate hydrates K4{M II[H(SO4)2]2(H2O)2}, where M II = Mn or Zn, are synthesized, and their single-crystal structures are determined by X-ray diffraction. The structural units of the orthorhombic crystals (space group Pccn) are potassium and M II cations, SO 4 2? and HSO 4 ? anions, and water molecules. Strong (2.52 Å) and moderate-in-strength (2.71–2.75 Å) hydrogen bonds link the anions and water molecules into hexamers. The M II cations, which have the octahedral environment (Mn-O, 2.14–2.19 Å and Zn-O, 2.07–2.11 Å), link the hexamers into flat layers. The structures of bimetallic hydrogen chalcogenate hydrates with different compositions are compared. 相似文献
7.
N. A. Yamnova Yu. K. Egorov-Tismenko O. V. Dimitrova A. P. Kantor 《Crystallography Reports》2002,47(4):566-573
In the process of studying the phase formation in the Li2CO3-CaO-B2O3-NaCl system, new Ca,Na, Li-carbonate-borate has been synthesized under hydrothermal conditions. The crystal structure of carbonate-borate with the crystallochemical formula Ca4(Ca0.7Na0.3)3(Na0.7□ 0.3)Li5[B 12 t B 10 Δ O36(O,OH)6](CO3)(OH) · (OH,H2O) was refined to R hkl = 0.0716 by the least squares method in the isotropic approximation of atomic thermal vibrations without the preliminary knowledge of the chemical composition and the formula (sp. gr. R3, a rh = 13.05(2) Å, α = 40.32(7)]°, V = 838(2) Å3, a h = 8.99(2), c h = 35.91(2) Å, V = 2513(2) Å3, Z = 3, d calcd = 2.62 g/cm3, Syntex P $\bar 1$ diffractometer, 3459 reflections, 2θ-θ method, λMo). The structure has a new boron-oxygen radical [B 12 t B 10 Δ O36(O,OH)6] ∞∞ 15? , a double layer of nine-membered [B 6 t B 3 Δ O15(O,OH)3]7.5?-rings bound by BO3-triangles, and twelve-membered [B 6 t B 6 Δ O19.5(O,OH)3]7.5? rings. This allows one to relate this compound to megaborates with complex boron-oxygen radicals. The structure is built from two types of blocks consisting of Ca,Na,B-and Li,B-polyhedra alternating along the c-axis, which explains the perfect cleavage of the crystals along the (0001) plane. 相似文献
8.
Single crystals of acid salt hydrates M I{M II[H(XO4)2](H2O)2}, where M I, M II, and X are K, Zn, and S (I); K, Mn, and S (II); Cs, Mn, and S (III); or K, Mn, and Se (IV), respectively, were synthesized and studied by X-ray diffraction analysis. Compounds I–IV (space group $P\bar 1$ ) are isostructural to each other and to hydrate KMg[H(SO4)2](H2O)2 (V) studied earlier. Structures I–V, especially, the M I-O, M II-O, and X-O distances and the O?H?O (2.44–2.48 Å) and Ow-H?O (2.70–2.81 Å) hydrogen bonds, are discussed. 相似文献
9.
V. I. Burkov A. F. Konstantinova B. V. Mill T. F. Veremeĭchik Yu. N. Pyrkov V. P. Orekhova E. V. Fedotov 《Crystallography Reports》2009,54(4):613-618
The absorption and circular dichroism spectra of langasite family crystals, La3Ga5SiO14, La3Ga5GeO14, Ca3Ga2Ge4O14, Sr3Ga2Ge4O14 (red), Sr3Ga2Ge4O14 (green), La3Ta0.5Ga5.5O14, and La3Nb0.5Ga5.5O14, which were doped with chromium ions, have been investigated in the range of 240–850 nm. It is shown that chromium ions are incorporated into the structure of the investigated crystals both in the octahedrally (Cr3+ ion in 1a octahedron) and tetrahedrally (Cr4+ ion in 2d tetrahedron) coordinated positions. The ion ratio Cr3+/Cr4+ changes in a wide range in the crystals studied. 相似文献
10.
The crystal structures of Cs[CuB10H10] (I) and (CH3)2NH2[CuB10H10] (II) are studied (R = 0.0398 and 0.0510 for 1225 and 2728 observed reflections in I and II, respectively). Crystals I and II are built of [(CuB10H10)?]∞ anionic chains and cations. The distorted tetrahedral coordination of the Cu+ ions is formed by four pairs of B-H atoms from two polyhedral anions. The Cu-B bond lengths in I and II are 2.159–2.287(6) and 2.130–2.285(9) Å, respectively. The coordination of the Cu+ ions in II includes only edges between apical and equatorial vertices of the anions. In I, both the edges of the apical belt and those between two equatorial vertices are involved in coordination. The ability of the B10H 10 2? anion to coordinate metals by the equatorial edge is established for the first time. 相似文献
11.
A. V. Zalesskii M. K. Gubkin T. M. Perekalina T. A. Khimich 《Crystallography Reports》2000,45(4):678-681
Spin-lattice (T 1) and spin-spin (T 2) relaxation times of 57Fe nuclei in the single-crystal NiFe2O4 and CoFe2O4 ferrites containing Fe2+ ions have been studied in the temperature range of 4.2–100 K by a spin-echo technique. The peaks of relaxation rates T 1 ?1 and T 2 ?1 caused by the presence of Fe2+ ions were observed for both ferrites in the ranges 38–42 and 28–32 K, respectively. The analysis of the results obtained with invocation of the data on ferromagnetic resonance and the measurements of the temperature dependence of resistivity shows that the mechanism of nuclear relaxation responsible for “impurity” peaks and is a slow relaxation process caused by electron exchange Fe2+ ? Fe3+, characterized by a low activation energy. 相似文献
12.
V. S. Sergienko I. I. Seifullina E. E. Martsinko A. B. Ilyukhin 《Crystallography Reports》2013,58(2):237-240
The barium salt of 1-oxyethylidenediphosphonatohydroxogermanium acid Ba3[Ge(μ-OH)(μ-Oedph)]6 · 25H2O (I) (H4Oedph is 1-oxyethylidenediphosphonic acid) was synthesized and studied by X-ray diffraction. The complex was characterized by elemental analysis, thermogravimetry, and IR spectroscopy. The hexanuclear cyclic complex anions [Ge(μ-OH)(μ-Oedph)] 6 6-t- ] cations, and water molecules of crystallization are the structural units of the crystal of I. 相似文献
13.
《Journal of Non》2006,352(40-41):4346-4350
The present contribution presents X-ray absorption fine structure (XAFS) measurements and analysis of the Ge and Ga local structure in glass of Ca3Ga2Ge3O12 composition, doped with rare-earth metals (Ce, Eu, Ho, Er in the amount of 0.7 wt% and Nd in the amount of 1.0 wt%). The Ge and Ga ion neighborhoods in the considered glass samples have been compared with data obtained for undoped glass. The results have shown that introduction of rare-earth ions modifies the local structure around the Ga ions in the glass network, leaving the same occurrence ratio of the GaO4 and GaO6 structural units as in undoped Ca3Ga2Ge3O12 glass. At the same time, the GeO2 subsystem remains completely unaffected by the presence of rare-earth dopants. 相似文献
14.
R. A. Khasanov N. M. Nizamutdinov N. M. Khasanova V. M. Vinokurov G. S. Morozov A. O. Krivtsov 《Crystallography Reports》2012,57(5):751-757
The conditions for equivalent positions on the (hkl) face of growing crystal are derived using symmetry elements of the space group. It is shown by the example of the sp. gr. D 2h 16 that the conditions of equivalent position formation coincide with conditions of the reflection of diffracted beams by crystal. It is established that electron spin resonance (ESR) centers in barite, SO 4 ? (I) and SO 4 ? (II), with only two conjugate spectra with equal intensity out of four, and SO 4 ? (III), with a different intensity of conjugate spectra K ??M = 2, are localized into the growth pyramid of the (001) face with a [010] step. SO 2 ? , SO 3 ? ,, and SO 4 ? (IV) centers, having an identical intensity of the conjugate ESR spectra with K ??M = 2, are localized into the growth pyramid of the (210) face with a growth step [001]. 相似文献
15.
The crystal structure of a new synthetic potassium gallophosphate K3Ga2(PO4)3 grown from a solution in the melt of a mixture of GaPO4 and K2MoO4 is determined using X-ray diffraction (Bruker Smart diffractometer, 2θmax= 56.6°, R = 0.044 for 2931 reflections, T = 100 K). The main crystal data are as follows: a = 8.661(2) Å, b = 17.002(4) Å, c = 8.386(2) Å, space group Pna21, Z= 4, and ρcalcd = 2.91 g/cm3. The synthesized crystals represent the third phase in the structure type previously established for the K3Al2[(As,P)O4]3 compound. It is shown that the structure consists of a three-dimensional anionic microporous tetrahedral framework of the mixed type, which is formed by PO4 and GaO4 tetrahedra shared by vertices. Large-sized cations K+ occupy channels of the zeolite-like framework. The crystal chemical features of the formation of structure types of compounds with mixed frameworks described by the general formula A 3 + M 2 3+ (TO4)3 (where A = K, Rb, (NH4), Tl; M = Al, Ga, Fe, Sc, Yb; T = P, As) are analyzed. 相似文献
16.
The crystal structure of natural titanium-containing ludwigite has been refined. The unit-cell parameters are a = 9.260 ± 0.002 Å, b = 12.294± 0.002 Å, c = 3.0236± 0.0005 Å, sp. gr. Pbam, and R = 0.0288. The observed cation distribution over the M1-M4 positions corresponds to the structural formula (Mg0.5)(Mg1.0)(Mg0.338Fe 0.162 2+ )(Fe 0.47 3+ Ti 0.21 4+ Mg 0.15 2+ Al 0.10 3+ Fe 0.07 2+ (BO3)O2. Highly charged titanium ions in the M4 position are balanced mainly with magnesium and not with divalent iron ions. 相似文献
17.
Polycrystalline samples in the ternary system La2Mo2O9-Sm2W2O9-Sm2Mo2O 9 + were synthesized in air. The region of the existence of compounds with the lanthanum molybdate (La2Mo2O9) structure in this system was determined. The polymorphism of the synthesized compounds was studied. Doping with samarium or with samarium and tungsten was shown to lead to the suppression of the transition between the monoclinic and cubic phases α → β and the appearance of the transition β ms → β between two cubic phases. In samples with a high samarium content, the phase transition β ms → β manifests itself as significant anomalies in the temperature dependences of the dielectric permeability and electric conductivity. An increase in the concentration of samarium in the samples leads to a substantial decrease in the conductivity compared with the nondoped compound La2Mo2O9. 相似文献
18.
E. L. Belokoneva Yu. K. Kabalov A. G. Al-Ama O. V. Dimitrova V. S. Kurazhkovskaya S. Yu. Stefanovich 《Crystallography Reports》2002,47(1):17-23
Anhydrous oxygen-and lead-deficient lead borate of the composition Pb 0.9 (I) Pb 0.6 (II) [BO2.25]2 = 2Pb0.75[BO2.25] (sp. gr. P312) has been obtained by the hydrothermal synthesis. New acentric borate possesses optical nonlinearity comparable with the optical nonlinearity of α-quartz. The crystal structure of new borate is determined and refined by two X-ray diffraction methods—the single crystal diffractometry and the full-profile analysis. All the positions in the structure, except for those of the boron atom in the triangular coordination, are occupied only partly; one of the two lead positions is split. It is established that new borate is closely related to calcium carbonates—aragonite, calcite, and paralstonite. With an increase of the temperature, new borate undergoes the reversible phase transition into the centrosymmetric, most probably, aragonite-like phase. 相似文献
19.
N. M. Olekhnovich 《Crystallography Reports》2006,51(2):169-177
A method for determining the strain characteristics of interatomic bonds in crystals of ternary oxides AB 1 2/′ B 1 2/″ O3 with perovskite structure, i.e., AB 1 2/′ B 1 2/″ O3 (B″ = Nb, Ta, Sb, Re, or Bi) and AB 1 2/′2+ B 1 2/″6+ O3 (B″ = Mo, W, Re, Os, or U), is developed. A linear relationship is established between the effective lengths of unstrained B-O bonds (l 0BO) and the lengths of unstrained B′-O (l 0B′O) and B″-O (l 0B″O) bonds, which differs from the Vegard rule. The found values of l 0B″O for ternary oxides with perovskite structure turned out to be close to the average interatomic B″-O distances in crystals of polymorphic phases of low-symmetry simple oxides. It is shown that the average length of the unstrained Pb-O bond in PbB 1 2/′ B 1 2/″ O3 perovskites corresponds to the length of the same bond in binary oxides PbBO3. For ternary oxides with perovskite structure, a linear correlation between the bond-strain energy and the temperature of their transition to the cubic phase is established. A linear correlation is found between the ratios of the Curie temperatures and the bond-strain energy for lead niobates and tantalates. 相似文献
20.
N. A. Ovchinnikova A. E. Sinyakov V. S. Sergienko G. G. Aleksandrov 《Crystallography Reports》2003,48(4):602-605
A product of the insertion of two isothiocyanate molecules into the same W-Cl bond, namely, W-Cl-WCl5{N(Et)C(S)N(Et)C(S)Cl} (I), is synthesized by the reaction of WCl6 with EtNCS in a dichloroethane solution. The hydrolysis of compound I results in the formation of single crystals of the complex . The structure of crystals II is determined using X-ray diffraction. It is demonstrated that structural units of crystals II are the [WVIOCl5]? anionic complexes and the ethyl-(4-ethyl-5-thioxo[1.2.4]dithiazolidin-3-ylidene)ammonium cations. 相似文献