Crystal Structure of a New Form of Cu3V2O8

1972 ◽  
Vol 50 (24) ◽  
pp. 3944-3949 ◽  
Author(s):  
Robert D. Shannon ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Unit Cell ◽  
Teller Effect ◽  
Space Group ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
New Form

A new form of Cu3V2O8 was prepared at 30 kbar and 900 °C. The unit cell has dimensions a = 6.2493(9), b = 7.9936(9), c = 6.3776(10) Å, β = 111.49(1)°, and the space group is P2/c. The crystal structure, refined by least-squares to a final R = 0.054, using 848 reflections, is similar to that of Mg3V2O8. Chains of edge-shared M2 octahedra run along the c axis at about y = ± 1/4 with M1 octahedra sharing two edges with the M2 octahedra. These octahedral networks at about y = ± 1/4 are linked by corner-shared V–O tetrahedra. The distortion from the Mg3V2O8 structure can be explained on the basis of the Jahn–Teller effect in which four of the octahedral Cu—O distances shorten to 1.93–1.99 Å and two Cu—O distances lengthen to 2.3–2.6 Å.

Preparation and Crystal Structure of a New Lithium Vanadium Fluoride Li2VF6 with Trirutile-type Structure

2013 ◽  
Vol 68 (2) ◽  
pp. 121-126 ◽  
Author(s):  
Suliman Nakhal ◽  
Dominik Weber ◽  
Martin Lerch
Keyword(s):  
Crystal Structure ◽  
Lithium Fluoride ◽  
Lattice Parameters ◽  
Type Structure ◽  
Teller Effect ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Jahn Teller ◽  
Jahn Teller Effect

A new lithium vanadium fluoride Li2VF6 was prepared by reacting lithium fluoride LiF with vanadium tetrafluoride VF4 in a monel capsule at 500 °C. The crystal structure has been determined by means of powder X-ray diffraction. Trirutile-type dilithium hexafluorovanadate(IV) crystallizes in the tetragonal space group P42/mnmwith lattice parameters a=459.99(1), b=459:99(1), c=896.64(2) pm. The presence of a Jahn-Teller effect is discussed.

Neue Mangan(III)-Fluoridhydrate: Na[MnF4(H2O)2] und Na[MnF4(H2O)2] · H2O / New Fluoride Hydrates of Manganese(III): Na[MnF4(H2O)2] and Na[MnF4(H2O)2] · H2O

1990 ◽  
Vol 45 (5) ◽  
pp. 593-597 ◽  
Author(s):  
Werner Massa ◽  
Roland E. Schmidt
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Teller Effect ◽  
Crystal Structure Determination ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Jahn Teller ◽  
Jahn Teller Effect

Crystalline Na[MnF4(H2O)2] and Na[MnF4(H2O)2] · H2O have been precipitated from aqueous HF solution of MnO(OH) and NaF. The crystal structure determination of the trihydrate (space group C 2/c, Z = 8, α = 1638.1(2), b = 667.6(2), c = 1130.3(1) pm, β = 103.78(1)°; R/wR = 0.038/0.033 for 1696 independent reflections) showed the presence of isolated octahedral trans-[MnF4(H2O)2]- anions with an elongation of the H2O-Mn—OH2 axis due to the Jahn-Teller effect (Mn 1-O 224.6(2), Mn 1—F(mean) 183.7(1); Mn2-0 218.3(2), Mn2— F(mean) 184.7(2) pm). As a consequence, an unusual H-bond geometry is observed with a tetrahedral (instead of trigonal) environment of the coordinated O atoms. Na[MnF4(H2O)2] is monoclinic (space group C 2/m, C 2 or Cm, a = 816.6(4), b = 677.1(1), c = 496.8(2), β = 114.45(3)°), the crystals show twinning and 1-dimensional disorder.

The crystal structure of fedotovite, K2Cu3O(SO4)3

1991 ◽  
Vol 55 (381) ◽  
pp. 613-616 ◽  
Author(s):  
G. L. Starova ◽  
S. K. Filatov ◽  
V. S. Fundamensky ◽  
L. P. Vergasova
Keyword(s):  
Crystal Structure ◽  
Copper Atom ◽  
Teller Effect ◽  
Coordination Polyhedra ◽  
Coordination Environment ◽  
Space Group ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Oxygen Atoms

AbstractThe crystal structure of fedotovite, K2Cu3O(SO4)3 has been determined, space group C2/c, a 19.037(6), b 9.479(2), c 14.231(5) Å, β 111.04(3)°, Z = 8, Dx = 3.09 g/cm3. The main units of the fedotovite structure are formed around two additional oxygen atoms and consist of edge-sharing [OCu4] tetrahedra and four [SO4] tetrahedra attached to them. The units are further connected by two [SO4] tetrahedra, building distinct layers parallel to the yz plane. These layers are interconnected by potassium atoms. In the fedotovite structure, the three kinds of copper atoms are fivefold (4 + 1) coordinated to oxygen atoms with a strong Jahn-Teller effect. The coordination polyhedra of Cu1 and Cu2 atoms are distorted and flattened orthorhombic pyramids with Cu-O distances varying from 1.912 to 2.333 Å, the sixth neighbour of the both atoms is the copper atom lying at 2.975 and 2.981 Å for Cu2 and Cu1 respectively. The coordination environment of the Cu3 atom is a distorted elongated orthorhombic pyramid with four Cu-O distances from 1.943 to 1.961 Å, a fifth at 2.558 Å, and further sixth and seventh neighbours (oxygen and copper atoms) at 2.809 and 2.806 Å, respectively.

Refinement of the structure of Mg2As2O7

1970 ◽  
Vol 48 (6) ◽  
pp. 890-894 ◽  
Author(s):  
C. Calvo ◽  
K. Neelakantan
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Least Squares ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Cell Dimensions ◽  
Central Oxygen ◽  
R Value ◽  
Unit Cell Dimensions

The crystal structure of Mg2As2O7 has been refined by full matrix least squares procedures using 587 observed reflections. The structure of Mg2As2O7 is of the thortveitite type, as reported by Łukaszewicz, with space group C2/m and unit cell dimensions a = 6.567(2) Å, b = 8.524(4) Å, c = 4.739(1) Å, β = 103.8(1)°, and Z = 2. The As—O—As group in the anion appears to be linear but the central oxygen atom undergoes considerable disorder in the plane perpendicular to this group. The AsO bond distances uncorrected for thermal motion are 1.67 Å for the As—O(—As) bond and 1.66 and 1.65 Å for the terminal As—O bonds. The final R value obtained is 0.088.

Crystal structure of triclinic rubidium dichromate, Rb2Cr2O7

1970 ◽  
Vol 48 (4) ◽  
pp. 537-543 ◽  
Author(s):  
N. Ch. Panagiotopoulos ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Dichromate Ions ◽  
Oxygen Atoms

The crystal structure of triclinic rubidium dichromate has been determined by single crystal X-ray diffraction. The crystal belongs to space group [Formula: see text] with a = 13.554, b = 7.640, c = 7.735 Å, α = 93.64°, β = 98.52°, γ = 88.80° and has four Rb2Cr2O7 units in the unit cell. The final weighted agreement index after refinement by least-squares analysis is 0.058. The configuration of the dichromate ions is similar to that found in most other dichromate structures (Cr—O (bridging) = 1.78 Å, Cr—O (terminal) = 1.62 Å). The two non-equivalent Cr—O—Cr angles are 123 and 137°. The rubidium ions are surrounded by either 8 or 9 oxygen atoms at distances ranging from 2.86 to 3.31 Å. The structure of triclinic Rb2Cr2O7 is similar, but not identical, to that of triclinic K2Cr2O7.

Refinement of the Crystal Structure of the Low-quartz Modification of Ferric Phosphate

1975 ◽  
Vol 53 (14) ◽  
pp. 2064-2067 ◽  
Author(s):  
Hok Nam Ng ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Room Temperature ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Ferric Phosphate ◽  
R Value

The structure of ferric phosphate at room temperature was refined on a Dauphiné-twinned crystal using full-matrix least-squares methods. The final R value was 0.078 for 487 symmetry-independent reflections whose intensities were corrected for twinning. The structure was found to be isotypic with AlPO4 (berlinite) with the space group P3121 and four formula units in a unit cell defined by a = 5.036(2) and c = 11.255(4) Å. The structure is also closely related to that of α-quartz with a nearly doubled c-axis because of the ordering of Fe and P atoms. The PO4 tetrahedron is almost regular with a mean P—O distance of 1.526 Å. The Fe3+ ion is tetrahedrally coordinated with an average Fe—O distance of 1.853 Å.

Die Kristallstruktur des Trichlorphons C4H8O4PCl3

1969 ◽  
Vol 24 (9) ◽  
pp. 1071-1074 ◽  
Author(s):  
E. Höhne ◽  
Kh. Lohs
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Unit Cell ◽  
Fourier Methods ◽  
Space Group ◽  
R Factor ◽  
Anisotropic Temperature ◽  
Temperature Factors ◽  
Atomic Coordinates

The crystal structure of trichlorphon [O,O-Dimethyl- (1-hydroxy-2,2,2-trichlor-äthyl) -phosphonat] has been determined by PATTERSON and FOURIER methods. Space group P212121 with 4 molecules in a unit cell of dimensions α = 8,96 ± 0,03 A, b= 18,60 ± 0,05 Å, c = 5,80 ± 0,02 A were determined. Atomic coordinates and anisotropic temperature factors have been refined by the least squares method. The final R-factor is R (hkl) =0,102.

Crystal structure resolution of an insulator due to the cooperative Jahn–Teller effect through Bader's theory: the challenging case of cobaltite oxide Y114

2018 ◽  
Vol 47 (15) ◽  
pp. 5483-5491
Author(s):  
Christian Tantardini ◽  
Enrico Benassi
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Teller Effect ◽  
Jahn Teller ◽  
Jahn Teller Effect

Cobaltite YBaCo4O7, abbreviated as Y114, is one of the most thoroughly investigated perovskites, owing largely to its interesting magnetic properties.

Topotaktische Entwässerung von Cs2MnF5 · H2O zu Cs2MnF5 und die Kristallstrukturen beider Verbindungen / Topotactical Dehydration of Cs2MnF5 · H2O to Cs2MnF5 and the Crystal Structures of Both Compounds

1990 ◽  
Vol 45 (10) ◽  
pp. 1341-1348 ◽  
Author(s):  
Friedemann Hahn ◽  
Werner Massa
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Ferroelectric Properties ◽  
Type Structure ◽  
Water Molecules ◽  
Mean Values ◽  
Space Group ◽  
Jahn Teller ◽  
Jahn Teller Effect

Redetermination of the crystal structure of Cs2MnF5 · H2O (space group Cmm 2, Z = 2, a = 974.0(2), b = 867.4(1), c = 426.0(1) pm, R = 0.026 for 478 reflections) revealed ordered instead of disordered positions of water molecules indicating ferroelectric properties. The dehydration of a twinned crystal gave an untwinned single crystal of Cs2MnF5 by a topotactical reaction. The crystal structure of Cs2MnF5 (space group P4/mmm, Z = 1, a = 642.0(1), c = 422.9(1) pm, R = 0.034 for 175 reflections) shows trans-connected octahedral chains [MnF5]∞2- with 180° Mn-F-Mn bridge angles like in the monohydrate. The bridging bonds in Cs2MnF5 · H2O and in Cs2MnF5 resp. are elongated by the Jahn-Teller effect (mean values Mn-Fbridge 213/211, Mn-Fterm 184/186 pm). Cs2MnF5 represents the “aristotype” of the so- called Tl2AlF5 type structure family

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