Preparation and Crystal Structure of the Calcium Rhenate(VI, VII) Ca5Re3O15-x

1999 ◽  
Vol 54 (12) ◽  
pp. 1483-1488 ◽  
Author(s):  
Wolfgang Jeitschko ◽  
Horst A. Mons ◽  
Ute Ch. Rodewald
Keyword(s):  
Crystal Structure ◽  
The Other ◽  
Oxidation Number ◽  
Variable Parameters ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Oxygen Coordination ◽  
Structure Factors ◽  
Oxygen Site ◽  
Elemental Calcium

The title compound was prepared by reaction of elemental calcium with the calcium metaperrhenate Ca(ReO4)2. Its crystal structure was determined from single-crystal X-ray data: Amm2, a = 560.31 (5)pm, b = 1572.4( 1)pm, c = 719.91 (6)pm ,Z = 2 ,R = 0.033 for 930 structure factors and 46 variable parameters. The calcium atoms occupy three atomic sites, all with seven oxygen neighbors. Of the two different rhenium atoms one has square-pyramidal oxygen coordination with an average oxidation number +6.25. The other rhenium site (oxidation number +7) was refined as a split position with trigonal-bipyramidal (75%) and tetrahedral oxygen coordination (25%). One oxygen site remains unoccupied, whenever the tetrahedral rhenium site is occupied, resulting in the composition Ca5Re3O14.75. A test for superconductivity of this black compound down to 1.5 K was negative.

Organoamido- and Aryloxo-Lanthanoids. XI. Syntheses and Crystal Structures of Nd(Odpp)3, Nd(Odpp)3(thf) and [Nd(Odpp)3(thf)2].2(thf) (Odpp-=2,6-Diphenylphenolate): Variations in Intramolecular π-Ph-Nd Interactions

1995 ◽  
Vol 48 (4) ◽  
pp. 741 ◽  
Author(s):  
GB Deacon ◽  
TC Feng ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Phenyl Group ◽  
Triangular Array ◽  
The Other ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Distorted Trigonal Bipyramidal

The X-ray crystal structure of Nd (Odpp)3 ( Odpp- = 2,6-diphenylphenolate), obtained by sublimation of Nd ( Odpp )3( thf )2 ( thf = tetrahydrofuran ) [triclinic, Pī , a 15.835(5), b 13.499(10), c 10.955(11) Ǻ, α 116.25(7), β 92.87(7), γ 101.66(6)°, V 2031 Ǻ3, Z2, No 5726 'observed' data (I > 3σ(I)) refined to conventional R 0.047 shows a near triangular array of oxygens surrounding neodymium { Nd -O} 2.169 Ǻ, ∑ O- Nd -O 353.2° with additional, intramolecular Nd-η6-Ph chelate interactions { Nd -C} 3.046 Ǻ and Nd-η1-Ph ( Nd -C 2.964(7)Ǻ). There is a pseudotrigonal bipyramidal arrangement of the oxygens, the centroid of the η6-Ph, and the η1-carbon. The complex Nd ( Odpp )3( thf ), obtained by crystallization of Nd ( Odpp )3( thf )2 from toluene (monoclinic, P21/c, a 12.213(4), b 21.447(4), c 17.744Ǻ, β 104.25(2)°, V 4505 Ǻ3, Z 4, R 0.042 for No 8014) also has pseudotrigonal bipyramidal stereochemistry, with a triangular equatorial array of aryl oxide oxygens { Nd -O} 2.193 Ǻ; ∑ O- Nd -O 358.7°, an apical thf oxygen (Nd -O 2.446(3)Ǻ), and an apical intramolecular chelating phenyl group. As the last has three Nd -C contacts (3.094(5), 3.144(5), 3.010(5)Ǻ) significantly shorter than the other three (3.300(5), 3.427(5), 3.377(5)Ǻ), an η3-Ph-Nd interaction seems likely. For [ Nd ( Odpp )3( thf )2].2( thf ), obtained by crystallization from tetrahydrofuran without drying of the crystals, the X-ray structure (monoclinic, P21, a 10.230(2), b 21.919(5), c 13.411(4) Ǻ, β 101.15(2)°, V 2950 A3, Z2, R 0.058 for No 3237) reveals a distorted trigonal bipyramidal arrangement of three aryl oxide oxygens (two equatorial 2.208(9), 2.16(1) Ǻ; one axial 2.203(9) Ǻ) and two thf oxygens (one equatorial 2.44(1) Ǻ; one axial (significantly distant) 2.62(1) Ǻ). The X-ray structure of [La( Odpp )3( thf )2].2( thf ) shows it to be isostructural with the neodymium analogue.

Er5Re2C7, Tm5Re2C7, and Lu5Re2C7 with Sc5Re2C7 Type, and Yb2ReC2 with Pr2ReC2 Type Structures

1997 ◽  
Vol 52 (2) ◽  
pp. 231-236 ◽  
Author(s):  
R. Pöttgen ◽  
K. H. Wachtmann ◽  
W. Jeitschko ◽  
A. Lang ◽  
T. Ebel
Keyword(s):  
Magnetic Susceptibility ◽  
Bond Length ◽  
High Frequency ◽  
Annealing Process ◽  
Type Structure ◽  
The Other ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors

Abstract Er5Re2C7, Tm5Re2C7, and Lu5Re2C7 were prepared by arc-melting of the elemental components and subsequent annealing at 800 °C. Er5Re2C7 forms only after the annealing process, whereas the other two carbides were already present in the as cast samples. They crystallize with a Sc5Re2C7 type structure, which was refined from single-crystal X-ray data of Lu5Re2C7: Cmmm, a = 791.44(5), b = 1418.08(8), c = 332.79(2) pm, Z = 2, R = 0.037 for 544 structure factors and 21 variable parameters. The structure contains linear centrosymmetric C3 units with a C-C bond length of 133(2) pm and isolated carbon atoms in octahedral coordination of four lutetium and two rhenium atoms. The rhenium atoms within the two-dimensionally infinite polymeric sheets [Re2C4]n are electronically saturated as is indicated by the diamagnetism and the semiconductivity of this carbide. Yb2ReC2 was prepared by reacting the elements in a sealed tantalum tube with a high-frequency furnace. It crystallizes with a Pr2ReC2 type structure: Pnma, a = 645.91(6), b = 498.64(6), and c = 966.05(6) pm. Magnetic susceptibility measurements indicate the ytterbium atoms to be trivalent in this compound.

Multianvil High-Pressure Synthesis And Crystal Structure Of β-YbBO3

2001 ◽  
Vol 56 (8) ◽  
pp. 697-703 ◽  
Author(s):  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Title Compound ◽  
Variable Parameters ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Oxygen Coordination ◽  
Distorted Octahedral ◽  
Pressure Synthesis ◽  
Octahedral Oxygen

β-Ytterbium borate (β-YbBO3) was synthesized under high-pressure in a Walker-type multianvil apparatus at 2.2 GPa and 1400 °C. The title-compound crystallizes in the trigonal calcite structure, space group R3̄̄c. Single crystal X-ray data yielded a = 492.1(2), c = 1630.5(9) pm, wR2 = 0.0344 for 165 F2 values and 11 variable parameters. Within the trigonal planar BO3 groups the B-O distance is 137.8(4) pm. The ytterbium atoms have a slightly distorted octahedral oxygen coordination (Yb-O: 224.4(2) pm)

Organoamido- and Aryloxo-lanthanoids. X. Tris(η2-3,5-di-t-butylpyrazolato)lanthanoid(III) Complexes and the X-Ray Crystal Structure of Er(η2-But2pz)3(thf)2

1994 ◽  
Vol 47 (7) ◽  
pp. 1223 ◽  
Author(s):  
JE Cosgriff ◽  
GB Deacon ◽  
BM Gatehouse ◽  
H Hemling ◽  
H Schumann
Keyword(s):  
Crystal Structure ◽  
Triphenylphosphine Oxide ◽  
The Other ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Oxygen Atoms

The complexes Ln (But2pz)3( thf )2 ( Ln = Y, La, Pr, Nd , Sm, Gd, Dy , Er , Yb, Lu; But2pz- = 3,5-di-t-butylpyrazolate; thf = tetrahydrofuran ), and [ Ln (But2pz)3(OPPh3)2].( dme )n ( Ln = La, n = ⅔ ; Ln = Er , n = 1; dme = 1,2-dimethoxyethane) have been prepared by reaction of the lanthanoid metal with bis ( pentafluorophenyl )mercury and the corresponding pyrazole in either thf , or in dme in the presence of triphenylphosphine oxide. The X-ray crystal structure of Er (η2-But2pz)3( thf )2 [monoclinic, space group P21 (No. 4), a 9.738(4), b 19.602(4), c 11.636(4) Ǻ, β 99.42(3)°, R 0.0374 for 3667 observed reflections] shows the complex to be an eight-coordinate monomer with three chelating But2pz ligands . The arrangement of centres ( Cen ) of the N-N bonds of the But2pz ligands [< Er -N> 2.336 Ǻ; Cen-Er-Cen 140.1(4)°, 110.3(4)° and 109.6(4)°] and the thf oxygen atoms [< Er -O> 2.351 Ǻ; O- Er -O 140.1(4)°] is intermediate between trigonal bipyramidal and square pyramidal. The other Ln (But2pz)3( thf )2 complexes and Ln (But2pz)3(OPPh3)2 are considered to have similar structures.

Tris [(trimethylsilyl)oxy] antimony

1994 ◽  
Vol 49 (7) ◽  
pp. 855-858 ◽  
Author(s):  
Michael Baier ◽  
Klaus Angermaier ◽  
Hubert Schmidbaur
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Gas Phase ◽  
Structure Determination ◽  
Spectroscopic Data ◽  
Mass Spectrometric ◽  
Unit Cell ◽  
The Other ◽  
X Ray ◽  
Trigonal Bipyramidal

Abstract Tris[(trimethylsilyl)oxy]antimony (Sb(OSiMe3)3, 1) has been prepared from SbCl3 and 3 equiv. of LiOSiMe3 in diethylether. According to mass spectrometric and NMR spectroscopic data, 1 appears to be a monomer in solution and in the gas phase. Dimerisation occurs, however, in the solid state as verified by an X-ray crystal structure determination. The unit cell contains three crystallographically independent monomers, two of which form one type of dimer, while the other is part of a centrosymmetrical dimer. In both types of dimers two Sb atoms are connected via two OSiMe3 groups to form distorted Sb2O2-squares. Together with the remaining 4 OSiMe3 groups and the two stereochemically active lone pairs, each Sb exhibits a trigonal bipyramidal coordination.

scholarly journals Preparation and Crystal Structure of the Carbides Ln12Re5C15 (Ln = Y, La-N d, Gd-Er)

1994 ◽  
Vol 49 (8) ◽  
pp. 1081-1088 ◽  
Author(s):  
Rainer Pöttgen ◽  
Günter Block ◽  
Wolfgang Jeitschko ◽  
Ronald K. Behrens
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Formula Unit ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors

The title compounds were prepared by arc-melting of the elemental components and sub­sequent annealing. Their crystal structure is hexagonal P 6̅ 2 m with one formula unit per cell. It was determined from single-crystal X-ray data of La12Re5C15 (a =1116.8(1) pm, c =545.3(1) pm, R = 0.060 for 287 structure factors and 27 variable parameters) and Ho12Re5C15 (ia = 1066.7(1) pm, c = 504.2(1) pm, R = 0.018 for 392 F's and 31 variables). The structures correspond to the formula Ln12[ReC3]2[Re3C3(C2)3],where the brackets indicate two differ­ent trigonal planar anionic rhenium-carbon groups. The coordination of the rhenium atoms in these polyanions seems to be compatible with the 18-electron rule.

Zur Chemie der 1,3,5-Triaza-2-phosphorinan-4,6-dione. Teil IX. Umsetzungen einiger 1,3,5-Triorgano-1,3,5-triaza-2λ3-phosphorinan-4,6-dione mit Hexafluoraceton / Chemistry of the 1,3,5-Triaza-2-phosphorinan-4,6-diones. Part IX. Reaction of some 1,3,5-Triorgano-1,3,5-triaza-2λ3-phosphorinan-4,6-diones with Hexafluoroacetone

1995 ◽  
Vol 50 (12) ◽  
pp. 1785-1790 ◽  
Author(s):  
Ion Neda ◽  
Michael Farkens ◽  
Axel K. Fischer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Crystal Structure ◽  
Phosphorus Atom ◽  
Mass Spectra ◽  
Membered Ring ◽  
The Other ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Phosphoryl Compound ◽  
Spirocyclic Compounds

The reactions of 2-(2-chloroethyl)amino-1,5-dimethyl-3-phenyl-1,3,5-triaza-2λ3-phosphorinan- 4,6-dione (1), 2-bis(2-chloroethyl)amino-1,5-dimethyl-3-phenyl-1,3,5-triaza-2A3-phosphorinan- 4,6-dione (2), 2-methoxy-1,3,5-trimethyl-1,3,5-triaza-2λ3-phosphorinan-4,6-dione (3) and 2-trimethylsiloxy-1,3,5-trimethyl-1,3,5-triaza-2λ3-phosphorinan-4,6-dione (5) with hexafluoracetone are described. In the case of 2 and 3 the reaction furnished the spirocyclic compounds 7 and 8. 2-Bis(2-chloroethyl)amino-1,3,5-triphenyl-1,3,5-triaza-2λ3-phosphorinan- 4,6-dione (4) did not react. In the case of 1 and 5 rearrangement reactions took place; the (2-chloroethyl)amino substituent of 1 reacted with one of two equivalents of hexafluoroacetone with formation of the spirocyclic phosphorane 6. The reaction of 5 with tetrabromoorthobenzoquinone gave the phosphoryl compound 9. Compounds 6 - 8 were characterized via their 1H-, 13C-, 19F- and 31P-NMR and mass spectra, compound 9 via its 1H-, 13C- and 31P-NMR and mass spectra. An X-ray crystal structure determination of 8 was conducted; in the six-membered ring the phosphorus atom lies 73 pm out of the plane of the other atoms, and displays trigonal bipyramidal coordination.

Preparation and Crystal Structure of the Isotypic Carbides Ln3.67TC6 (Ln = rare earth elements; T = Mn, Fe, Ru) and Eu3,16NiC6

1996 ◽  
Vol 51 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Anne M. Witte ◽  
Wolfgang Jeitschko
Keyword(s):  
Crystal Structure ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Crystal Structures ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors

Abstract The 14 carbides Ln3.67MnC6 (Ln = La-Nd) and Ln3.67TC6 (Ln = La-Nd, Sm; T = Fe, Ru) were prepared from the elemental components by arc-melting and subsequent annealing. Eu3.16NiC6 was obtained from a lithium flux. The crystal structures of these nearly isotypic, hexagonal compounds (P63/m, Z = 2) were determined from single-crystal X-ray data; La3.67- FeC6: a = 878.7(2), c = 535.1(1) pm, R = 0.052 for 548 structure factors and 25 variable parameters; Eu3.16NiC6: a -860.0(1), c = 548.2(2) pm, R = 0.015 for 606 structure factors and 25 variables. The structures differ from the previously reported Gd3Mn2C6 structure by the occupancy of one manganese position by rare earth atoms. Since the lanthanum atoms are larger than the manganese atoms, only two thirds of these manganese positions can be occupied by the lanthanum atoms in La3.67FeC6. Eu3.16NiC6 has similar atomic positions. The C-C bond distances in the C2 pairs are 130(2) and 126.5(5) pm in the La and Eu compounds, respectively. Magnetic susceptibility measurements with a SQUID magnetometer indicate La3.67FeC6 to be Pauli paramagnetic. A test for superconductivity was negative down to 3 K.

Preparation, Properties, and Crystal Structure of Quaternary Silicide Carbides RCr2Si2C (R = Y, La - Nd, Sm, Gd - Ho)

2001 ◽  
Vol 56 (11) ◽  
pp. 1143-1148 ◽  
Author(s):  
Marc W. Pohlkamp ◽  
Wolfgang Jeitschko
Keyword(s):  
Crystal Structure ◽  
Bond Distance ◽  
Single Bond ◽  
Elemental Silicon ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors ◽  
Pauli Paramagnetism ◽  
Cold Pressed

The title compounds were prepared by arc-melting cold-pressed pellets of the elemental components. They crystallize with a tetragonal structure already reported for CeCr2Si2C. It was refined from single-crystal X-ray data of PrCr2S2C: P4/mmm, a - 402.2( 1) pm, c = 535.2(1) pm, Z = 1, R = 0.012 for 252 structure factors and 10 variable parameters. Magnetic susceptibility measurements with a SQUID magnetometer indicate Pauli paramagnetism for YCr2Si2C, while CeC2Si2C shows mixed valent behavior. The carbon atoms in the structure of these compounds are isolated from each other. The silicon atoms form pairs with a Si-Si distance of 245.3 pm, somewhat greater than the single-bond distance of 235.2 pm in elemental silicon. Together with the chromium atoms, the silicon pairs and carbon atoms form a three-dimensionally infinite polyanion, which has some similarity with the polyanions found in several related tetragonal structures, e.g., the structures of ThCr2Si2 and LuNi2B2C.

scholarly journals Synthesis and Crystal Structure of Hg2V8O20 – the First Ternary Mercury Vanadate with Mixed-valent Vanadium (IV/V)

2007 ◽  
Vol 62 (11) ◽  
pp. 1390-1396 ◽  
Author(s):  
Matthias Weil ◽  
Berthold Stöger ◽  
Annemarie L. Wessels ◽  
Wolfgang Jeitschko
Keyword(s):  
Crystal Structure ◽  
Structure Type ◽  
Vanadium Oxides ◽  
Near Neighbor ◽  
The Other ◽  
Intermediate Valence ◽  
Oxidation Number ◽  
Coordination Polyhedra ◽  
Variable Parameters ◽  
Synthesis And Crystal Structure

Black needle-shaped single crystals of Hg2V8O20 were obtained by heating amorphous precipitates resulting from mixing aqueous solutions of HgNO3OH and NH4VO3 (Hg :V ratios between 1 : 2.0 and 1 : 2.5) in evacuated silica ampoules at 450 °C for two weeks. Their crystal structure was determined from single crystal diffractometer data [C2/m, Z = 2, a = 22.375(1), b = 3.6312(2), c = 9.6113(4) Å, β = 91.708(5)°, R[F2 ≥ 2σ (F2)] = 0.0681, 807 F2 values, 61 variable parameters]. Two of the four independent vanadium atoms are surrounded by six close oxygen atoms whereas the other two have five oxygen neighbors. These coordination polyhedra share edges and corners resulting in puckered layers with an overall composition [V4O10]− extending parallel to (100). The layers are linked by Hg22+ dumbbells (d(Hg-Hg) = 2.510(2) Å) with a short Hg-O distance of 2.13(2) Å(∠(O9−Hg-Hg) = 173.8(5)°). Although Hg2V8O20 crystallizes in a new structure type, it resembles the structures of other layered vanadium oxides with open frameworks and can be classified as being of the Q-UD-type. The near-neighbor environments of the four vanadium positions of this reduced vanadate with an average oxidation number of +4.75 of the vanadium atoms are similar with respect to V-V bonding and it is suggested that the vanadium atoms have delocalized V-V bonding with intermediate valence.

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