scholarly journals Contributions to the stereochemistry of zirconium oxysalts—part III: syntheses and crystal structures of M2+Zr(SO4)3 with M = Mg, Mn, Co, Ni, Zn and Cd, and a note on (Fe3+,2+,Zr)2(SO4)3 and Fe2(SO4)3

2019 ◽  
Vol 150 (11) ◽  
pp. 1877-1892
Author(s):  
Gerald Giester ◽  
Dominik Talla ◽  
Manfred Wildner
Keyword(s):  
Mixed Valence ◽  
Structure Type ◽  
Minor Amount ◽  
The Novel ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Space Group ◽  
A Minor ◽  
Zirconium Oxysalts ◽  
Oxygen Bond

Abstract The novel compounds M2+Zr(SO4)3 with M = Mg, Mn, Co, Ni, Zn, and Cd as well as (Fe3+,2+,Zr)2(SO4)3 were synthesized at mild hydrothermal conditions (Teflon-lined stainless steel vessels, 220 °C) from the mixtures of Zr2O2(CO3)(OH)2, the respective M2+(SO4)·nH2O hydrated salts, H2SO4 and a minor amount of water. Crystals up to several tenths of a mm in size were obtained within a few days and studied at 200 K by single-crystal X-ray diffraction techniques. All these compounds belong to the structure type of monoclinic Fe2(SO4)3; they are either isotypic in space group P21/n (No. 14), Z = 4, i.e. M2+Zr(SO4)3 with M = Mn, Co, Ni, Zn, and Cd as well as the mixed valence sulfate (Fe3+,2+,Zr)2(SO4)3 or in the case of MgZr(SO4)3, closely related but with a larger unit cell, in space group Pc and Z = 8. The framework of the monoclinic Fe2(SO4)3 structure is characterized by two types of isolated Fe3+O6 octahedra, corner-linked with three types of sulfate groups. In the isotypic M2+Zr(SO4)3 series, the Fe3+ atom on the Fe(1) position is substituted by Zr4+ while M2+ ions occupy the Fe(2) site in the ferric sulfate structure type. Mean cation-oxygen bond lengths (S[4]: 1.462–1.472 Å; Zr[6]: 2.053–2.060 Å as well as M2+–O distances) are generally rather short, but still within the range reported in literature. Graphic abstract

A first Mn member in the struvite morphotropic series, CsMn(H2O)6(PO4): hydrothermal synthesis, crystal structure and interconnections within the family of related phosphates

2018 ◽  
Vol 74 (8) ◽  
pp. 936-943
Author(s):  
Galina V. Kiriukhina ◽  
Olga V. Yakubovich ◽  
Ekaterina M. Kochetkova ◽  
Olga V. Dimitrova ◽  
Anatoliy S. Volkov
Keyword(s):  
Crystal Structure ◽  
Ionic Radius ◽  
The Novel ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Cell Parameters ◽  
Structural Relationships ◽  
The Family

Caesium manganese hexahydrate phosphate, CsMn(H2O)6(PO4), was synthesized under hydrothermal conditions. Its crystal structure was determined from single-crystal X-ray diffraction data. The novel phase crystallizes in the hexagonal space group P63 mc and represents the first manganese member in the struvite morphotropic series, AM(H2O)6(TO4). Its crystal structure is built from Mn(H2O)6 octahedra and PO4 tetrahedra linked into a framework via hydrogen bonding. The large Cs atoms are encapsulated in the framework cuboctahedral cavities. It is shown that the size of the A + ionic radius within the morphotropic series AM(H2O)6(XO4) results is certain types of crystal structures and affects the values of the unit-cell parameters. Structural relationships with Na(H2O)Mg(H2O)6(PO4) and the mineral hazenite, KNa(H2O)2Mg2(H2O)12(PO4)2, are discussed.

K5[FeO4] und K17[Fe5O16]: Zwei neue Kalium-Oxoferrate(III) / K5[FeO4] and K17[Fe5O16]: Two New Potassium Oxoferrates(III)

2005 ◽  
Vol 60 (12) ◽  
pp. 1224-1230 ◽  
Author(s):  
Gero Frisch ◽  
Caroline Röhr
Keyword(s):  
Linear Chain ◽  
Reaction Times ◽  
Structure Type ◽  
Maximum Temperature ◽  
X Ray Diffraction ◽  
Tetrahedral Geometry ◽  
Space Group ◽  
X Ray ◽  
Subsequent Quenching ◽  
Rich Mixtures

The title compounds were synthesized from potassium rich mixtures of Fe2O3, elemental potassium and the hyperoxide KO2 by applying short reaction times, a maximum temperature of 875 K and subsequent quenching of the samples. The structures of the two new oxoferrates(III) have been determined by single crystal X-ray diffraction. The orthoferrate(III) K5[FeO4] (Na5[GaO4] structure type, space group Pbca, a = 1124,0(2), b = 667,95(9), c = 2034,8(3) pm, Z = 4, R1 = 0,0585) exhibits isolated ortho-anions [FeO4]5− with nearly ideal tetrahedral geometry and Fe-O distance in the narrow range of 189 to 192 pm. The pentaferrate K17[Fe5O16] (space group Cm, a = 671,71(5), b=3560,8(3), c=670,81(5) pm, β =119,687(5)°, Z =2, R1=0,0291) crystallizes with a new structure type. Its building units are isolated novel penta-nuclear anions composed of five corner sharing [FeO4] tetrahedra. These linear chain pieces [Fe5O16] are arranged in a hexagonal rod packing, with a stacking sequence according to |:AB:| along the large monoclinic b axis. The structure is thus related to that of the tetra-ferrate K14[Fe4O13] with a comparable packing of tetra-nuclear ferrate(III) anions.

Centrosymmetric or Noncentrosymmetric? Case Study, Generalization and Structural Redetermination of Sr5Nb5O17

1998 ◽  
Vol 54 (4) ◽  
pp. 399-416 ◽  
Author(s):  
S. C. Abrahams ◽  
H. W. Schmalle ◽  
T. Williams ◽  
A. Reller ◽  
F. Lichtenberg ◽  
...  
Keyword(s):  
Niobium Oxide ◽  
The Novel ◽  
Physical Measurement ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
Data Set ◽  
Space Group ◽  
X Ray ◽  
Atomic Coordinates

The possibility that the structure of the novel semiconducting perovskite-related material strontium niobium oxide, Sr5Nb5O17, refined by Schmalle et al. [Acta Cryst. (1995), C51, 1243–1246] in space group Pnn2, might instead belong to space group Pnnm has been investigated following an analysis of the atomic coordinates that indicated the latter space group to be more likely. All I obs were carefully remeasured, first those within a hemisphere containing c *, then all that lay within the full sphere of reflection. Refinement was undertaken, with each of two different sets of weights, in each space group. Each data set was used under three limiting intensity conditions: I obs > 4σ(I obs), I obs > 2σ(I obs) and finally with all reflections, but setting magnitudes with I obs ≤ 0 equal to 0. Fourteen separate tests based only upon the X-ray diffraction data may be used to distinguish between Pnn2 and Pnnm. Nine tests favored the latter choice, four were indeterminate and one was not used. Seven further tests may be made on the basis of physical measurement; of these, three strongly indicated Pnnm, one was indeterminate and three could not be used. The evidence clearly suggests the space group is Pnnm. The use of all reflections, including those with negative magnitude set equal to zero, is essential to avoid ambiguity in the X-ray diffraction tests and achieve the highest reliability. Refinement with weights based on variances of Type A and Type B [Schwarzenbach et al. (1995). Acta Cryst. A51, 565–569] resulted in improved reliability compared with that obtained from a popular empirical weighting scheme. The revised structure differs in several respects from that published previously.

AlkalineEarthMetal-Hydride-Iodide Compounds: Syntheses andCrystal Structures of Sr2H3I and Ba5H2I3.9(2)O2

2011 ◽  
Vol 66 (1) ◽  
pp. 21-26
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Structural Model ◽  
Structure Type ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Compounds

Single crystals of Sr2H3I andBa5H2I3.9(2)O2 were obtained by reacting Sr or Ba, respectively, with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules for 13 h at 1200 K. The crystal structures of the new compounds have been determined by means of single-crystal X-ray diffraction. Sr2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Ba2H3Cl in the space group P3m1 (no. 164) with the lattice parameters a = 426.0(1) and c = 774.9(2) pm, while Ba5H2I3.9(2)O2 crystallizes in a new structure type in the space group Cmcm (no. 63) with the lattice parameters a = 1721.0(2), b = 1452.5(2) and c = 639.03(9) pm. The structural results for Sr2H3I are corroborated by EUTAX calculations. For the disordered compound Ba5H2I3.9(2)O2, EUTAX calculations on an approximated, ordered structural model were used to find possible insights into the disorder

[ η6-C6Me6Fe- η5-C5H5]2Fe2Cl6 · 2 CH2Cl2: Bildung und Kristallstruktur / [η6-C6Me6Fe-η5-C5H5]2Fe2Cl6· 2CH2Cl2: Formation and Crystal Structure

1992 ◽  
Vol 47 (8) ◽  
pp. 1075-1078 ◽  
Author(s):  
Karin Ruhlandt-Senge ◽  
Ulrich Müller
Keyword(s):  
Crystal Structure ◽  
Ir Spectrum ◽  
Title Compound ◽  
The Novel ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

When hexymethylbenzene-cyclopentadienyl-iron reacts with ozone in dichloromethane, the title compound is one of the products. Its crystal structure was determined by X-ray diffraction (R = 0.145 for 1412 unique reflexions). Crystal data: a = 1815.1(8), b = 1314.8(5), c = 1823.0(8) pm, space group Pbca, Z = 8. The sandwich-like [η6-C6Me6Fe-η5-C5H5]+ ions exhibit large thermal motions, and the CH2C12 molecules are disordered in two orientations. The novel [Fe2Cl6]2- ion has the structure of two tetrahedra sharing an edge. Its IR spectrum is reported.

Preparation and Crystal Structures of the Isotypic Compounds CdXO4 · 2 HgO (X = S, Se)

2004 ◽  
Vol 59 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Matthias Weil
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Building Blocks ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Space Group ◽  
X Ray ◽  
Structure Factors

Colourless single crystals of the compounds CdXO4 · 2 HgO (X = S, Se) were obtained under hydrothermal conditions (250 °C, 5 d), starting from stoichiometric amounts of HgO, CdSO4 ·7H2O and CdSeO4 ·2H2O, respectively. The crystal structures were determined from X-ray diffraction data sets. The CdXO4 · 2HgO compounds crystallise isotypically with two formula units in space group P1̅ (# 2) [CdSO4 · 2HgO (CdSeO4 · 2HgO): a = 6.793(2) (6.9097(5)) Å , b = 7.205(2) (7.1786(6)) Å , c=7.359(2) (7.4556(6)) Å ,α =73.224(6) (74.586(2))°, β =66.505(6) (68.229(1))°, γ =63.054(5) (63.886(1))°, 1670 (1786) structure factors, 92 parameters, R[F2 > 2σ(F2)] = 0.0379 (0.0244)] and are made up from zig-zag [O-Hg-O]∞ chains with very short bonds of d̅(Hg-O) 2.025 Å , distorted [CdO6] octahedra (d̅(Cd-O)= 2.297 Å ), and XO4 tetrahedra (d̅(S-O)= 1.458 Å , d̅(Se-O)= 1.633 Å ) as the main building blocks. The CdXO4 ·2HgO compounds reveal no structural relationship with the corresponding HgXO4 ·2HgO phases

Structural and electrochemical properties of the binary silicides Eu5Si3 and EuSi

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bohdana Belan ◽  
Marek Daszkiewicz ◽  
Mariya Dzevenko ◽  
Beata Rożdżyńska-Kiełbik ◽  
Volodymyr Pavlyuk ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Specific Capacity ◽  
Structure Type ◽  
Electrochemical Process ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Electrochemical Lithiation ◽  
Charge Process ◽  
Oxford Diffraction

Abstract The crystal structures of Eu5Si3 and EuSi were studied in detail by X-ray single-crystal diffraction. The single crystals were selected from arc-melted and annealed samples. X-ray diffraction was performed at room temperature on an Oxford Diffraction X’calibur Atlas four-circle diffractometer (MoKα radiation). Eu5Si3 adopts the tetragonal Cr5B3-type: space group I4/mcm (# 140), Pearson code tI32, Z = 4, a = 7.9339(6), c = 15.308(2) Å. The compounds with equiatomic composition EuSi crystallize in the structure type TlI: space group Cmcm (# 63), Pearson code oS8, Z = 4, a = 4.6955(6), b = 11.1528(13), c = 3.9845(4) Å. The silicides Eu5Si3 and Li2Si form during electrochemical lithiation (charge process) of EuSi. The electrochemical process 5EuSi + 4Li+ + 4e − ↔ Eu5Si3 + 2Li2Si is reversible, and the discharge specific capacity at 1C rate reached 140 mAhg−1 and the Coulombic efficiency is 93%.

ζ-Y2[Si2O7]: Ein neuer Strukturtyp in der Yttrialit-Reihe / ζ -Y2[Si2O7]: A New Structure Type within the Yttrialite Series

2006 ◽  
Vol 61 (9) ◽  
pp. 1054-1060 ◽  
Author(s):  
Ingo Hartenbach ◽  
Steffen F. Meier ◽  
Thomas Schleid
Keyword(s):  
Single Crystals ◽  
Title Compound ◽  
Structure Type ◽  
Unit Cell ◽  
Type Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertex Sharing ◽  
A Minor ◽  
Oxygen Atoms

Abstract During attempts of preparing yttrium oxotellurates(IV) using Y2O3 and TeO2 in YCl3 fluxes, the occasional reaction of these educts with the walls of the evacuated silica ampoules led to colourless, lath-shaped single crystals of Y2[Si2O7] in the new ζ -type structure as a minor by-product which was investigated by X-ray diffraction. The title compound crystallizes monoclinically in the space group P21/m (a = 503.59(5), b = 806.47(8), c = 732.65(7) pm, β = 108.633(6)°) with two formula units per unit cell. The crystallographically unique Y3+ cation is coordinated by seven oxygen atoms (d(Y-O = 221 - 248 pm) arranged in the shape of a slightly distorted monocapped octahedron. The isolated oxodisilicate units [Si2O7]6− consist of two Si4+ cations and seven O2− anions of which five are crystallographically independent. These pyroanions (d(Si-O) = 161 - 168 pm, ∢ (O-Si-O) = 91 - 117°, ∢ (Si-O-Si) = 156°) exhibit an almost perfectly eclipsed conformation built of a horseshoeshaped backbone with the two silicon and three of the oxygen atoms situated on the mirror planes of the unit cell. The remaining four oxide anions complete this [Si2O7]6− entity of two vertex-sharing [SiO4]4− tetrahedra as terminal ligands for silicon. Assembled in planar layers parallel to (−1 0 1), the [Si2O7]6− anions are packed with their wide basal faces of the tetrahedra pointing towards the small waist of the adjacent units and vice versa. The yttrium cations reside between these layers in order to interconnect them three-dimensionally.

scholarly journals Disorder in a natural ixiolite: high resolution studies at 293 K and 120 K.

2014 ◽  
Vol 70 (a1) ◽  
pp. C1092-C1092
Author(s):  
Leandro Almeida ◽  
Douglas Miquita ◽  
Bernardo Rodrigues
Keyword(s):  
High Resolution ◽  
General Formula ◽  
Diffraction Data ◽  
High Mobility ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Independent Observations

Grice, Ferguson and Hawthorne [1] describes the ixiolite of Bernic Lake, Manitoba, Canada. According to these authors, the ixiolite is part of the Ixiolite-Tantalite-Wodgnite system and crystallizes in space group Pbcn, with general formula MO2, in a α-PbO2structure type. The structure of the mineral ixiolite from Volta Grande pegmatite, in Brazil, is herein described from high resolution (0.5 Å) X-ray diffraction data using MoKα radiation. This mineral has formula MO2, with M = Fe, Mn, Nb or Ta. Data were collected at 293 K and at 120 K from a well formed crystal (0.6 x 0.4 x 0.3 mm). 49868 and 32294 reflections were collected at 293 K and at 120 K, respectively. The structure of the ixiolite was well solved in both temperatures: at 293 K the mineral crystalizes in the space group Cmcm, and the structure was refined to R(F2)=0.0476, from 728 independent reflections. At 120 K, the mineral crystalizes in space group Pbcn, and the structure was refined to R(F2)= 0.0537 from 1357 independent observations. It is interesting to notice that the different space groups of the herein described ixiolite at 120 K (Pbcn) and at 293 K (Cmcm) is related to the different occupations of oxygen sites, as expected from the high mobility of oxygen atoms.

The crystal structures of CeSiO4 and Ca2Ce8(SiO4)6O2

2000 ◽  
Vol 15 (4) ◽  
pp. 234-238 ◽  
Author(s):  
J. M. S. Skakle ◽  
C. L. Dickson ◽  
F. P. Glasser
Keyword(s):  
Hydrothermal Synthesis ◽  
Nuclear Waste ◽  
Structure Type ◽  
Unit Cell ◽  
Apatite Structure ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Zircon Structure

Two new solubility-limiting phases relevant to nuclear waste disposal are reported, namely CeSiO4 and Ca2Ce8(SiO4)O2, produced by hydrothermal synthesis at 180 °C. X-ray diffraction data are presented for both compounds. Rietveld refinement was performed for each of these phases. CeSiO4 was confirmed to be a zircon structure type, with space group I41/amd, unit cell type="bold">abold=6.9564(3), type="bold">cbold=6.1953(4) Å. Bond lengths for SiO4 are in excellent agreement with published values; Ce4+ is coordinated to eight oxygen atoms with four regular and four short bonds. Ca2Ce8(SiO4)O2 was shown to have an apatite structure, with space group P63/m and unit cell type="bold">abold=9.4343(3), type="bold">cbold=6.8885(4) Å. The unit cell and bond lengths were found to be slightly smaller than would be expected from other lanthanide-containing analogs; possible reasons for this are discussed.

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