Search results for "Square antiprism"
showing 10 items of 16 documents
Synthesis and Crystal Structure of Ln3(OH)(CrO4)4 · 3.5H2O (Ln = Pr, Nd) and Ln2(OH)2(CrO4)2 (Ln = Tb, Gd): Thermal Behavior and Infrared Spectra of …
1993
Abstract Crystal structures of Ln 2 (OH) 2 (CrO 4 ) 2 ( Ln = Gd, Tb) and Ln 3 (OH)(CrO 4 ) 4 · 3.5H 2 O ( Ln = Pr, Nd) were determined by a conventional single-crystal X-ray diffraction technique. Crystals of Ln 2 (OH) 2 (CrO 4 ) 2 ( Ln = Gd, Tb) are monoclinic, space group P 2 1 / c (no. 14) with lattice parameters a = 8.2454(4) A, b = 11.3834(5) A, C = 12.1420(8) A, and β = 136,590(5)°, Z = 4, D x = 4.92 mg · m -3 for Gd 2 (OH) 2 (CrO 4 ) 2 and a = 8.214(1) A, b = 11.348(1) A, c = 12.094(2) A, and β = 136.59(1)°, Z = 4, D x = 5.01 Mg · m -3 for Tb 2 (OH) 2 (CrO 4 ) 2 . Crystals of Ln 3 (OH)(CrO 4 )) 4 · 3.5H 2 O ( Ln = Pr, Nd) are monoclinic, space group C 2/ c (No. 15) with lattice param…
Ti2Sn3: A Novel Binary Intermetallic Phase, Prepared by Chemical Transport at Intermediate Temperature
2000
Ti2Sn3 was obtained by chemical transport using iodine as the transport agent in a sealed quartz ampule at 500 °C. Its crystal structurea new type structurewas determined via single-crystal structure analysis to be orthorhombic, space group Cmca, a = 595.56(4), b = 1996.4(2), c = 702.81(5) pm, V = 835.6(1) × 106 pm3, and Z = 8. The structure can be derived from a three-dimensional condensation of a single polyhedron, which comprises a Ti atom in the center, surrounded by seven Sn and four Ti atoms forming a tri-capped square antiprism. Supporting the results of the self-consistent band structure calculations, Ti2Sn3 is a metallic p-type conductor, exhibiting Pauli paramagnetism and a specif…
One-dimensional oxalato-bridged heterobimetallic coordination polymers by using [the [Cr(pyim)(C2O4)2]− complex as metalloligand [pyim = 2-(2′-pyridy…
2019
Abstract Four new coordination polymers based on the use of the [Cr(pyim)(C2O4)2]− species as a metalloligand, namely [LiCr(pyim)(C2O4)2(MeOH)]n (1), {[CaCr2(pyim)2(C2O4)4]·2MeOH}n (2), {[SrCr2(pyim)2(C2O4)4(H2O)]·0.45MeOH·4.55H2O}n (3) and {[CdCr2(pyim)2(C2O4)4]·MeOH}n (4) [pyim = 2-(2′-pyridyl)imidazole] have been synthesized and characterized by elemental analyses, IR spectra and X-ray diffraction on single crystals. Complex 1 is a neutral heterobimetallic chain where the tris(chelated) chromium(III) unit acts as a bis-bidentate ligand towards {Li(MeOH)}+ fragments through its two oxalate ligands, each lithium ion being five-coordinate in a intermediate surrounding between square pyramid…
Rational Design of Single-Ion Magnets and Spin Qubits Based on Mononuclear Lanthanoid Complexes
2012
Here we develop a general approach to calculating the energy spectrum and the wave functions of the low-lying magnetic levels of a lanthanoid ion submitted to the crystal field created by the surrounding ligands. This model allows us to propose general criteria for the rational design of new mononuclear lanthanoid complexes behaving as single-molecule magnets (SMMs) or acting as robust spin qubits. Three typical environments exhibited by these metal complexes are considered, namely, (a) square antiprism, (b) triangular dodecahedron, and (c) trigonal prism. The developed model is used to explain the properties of some representative examples showing these geometries. Key questions in this ar…
Cyanido-Bridged {LnIIIWV} Heterobinuclear Complexes: Synthesis and Magneto-Structural Study
2017
A new series of cyanido-bridged {LnIIIWV} heterobinuclear complexes of formula [LnIII(pyim)2(i-PrOH)(H2O)2(μ-CN)WV(CN)7]·2H2O [Ln = Gd (1), Tb (2), Dy (3), Ho (4), and Er (5); pyim = 2-(1H-imidazol-2-yl)-pyridine) and i-PrOH = isopropyl alcohol] were synthesized by one-pot reaction between (NH3Bu)3[W(CN)8] and [Ln(pyim)2]2+ complexes (generated in situ by mixing the corresponding LnIII ions and the pyim ligand). Compounds 1–5 are isomorphous and crystallize in the monoclinic system P21/n space group. Their crystal structure consists of binuclear units in which the octacyanotungstate(V) anion coordinates to the corresponding LnIII ion through a single cyanide ligand. The tungsten(V) and lant…
The crystal structure of neodymium and europium chromate heptahydrate: Synthesis, infrared spectra, and thermal behavior of lanthanoid chromate hepta…
1991
Abstract The crystal structures of Nd2(CrO4)3 · 7H2O and Eu2(CrO4)3 · 7H2O were determined by the conventional single-crystal X-ray diffraction technique. In addition, unit cell dimensions were measured for La2 (CrO4)3 · 7H2O and Sm2(CrO4)3 · 7H2O. All these compounds are isostructural. Crystals are monoclinic, space group P2 1 c . For Nd2(CrO4)3 · 7H2O, a = 8.052(4) A, b = 19.143(4) A, c = 13.326(6) A, β = 128.15(4)°, Z = 4, Dx = 3.14 Mg · m−3, T = 296(1); and for Eu2(CrO4)3 · 7H2O, a = 7.965(3) A, b = 18.985(4) A, c = 13.185(4) A, β = 128.00(2)°, Z = 4, Dx = 3.29 Mg · m−3, T = 296(1). Ln atoms are nine-coordinated so that the coordination polyhedron is a tricapped trigonal prism for Ln1 a…
[Fe(phen)(CN)4]−: a suitable metalloligand unit to build 3d–4f heterobimetallic complexes with mixed bpym-cyano bridges (phen = 1,10-phenantroline, b…
2010
The synthesis, crystal structure and magnetic properties of a new series of mixed 3d–4f complexes with the formula [{FeIII(phen)(CN)3(μ-CN)}4Ln2III(NO3)2(H2O)6(μ-bpym)]·nH2O [Ln = Eu (1), Gd (2), Dy (3) and Ho (4); n = 8 (1, 3 and 4) and 11 (2); phen = 1,10-phenantroline; bpym = 2,2′-bipyrimidine] are discussed here. Compounds 1–4 are centrosymmetric hexanuclear species whose structure is made up of two cyano-bridged {Fe2IIILnIII} heterobimetallic moieties which are connected through a bis-bidentate bpym molecule between the two rare-earth centers. The values of the iron–lanthanide distance across the single cyano-bridge are Fe(1)⋯Eu(1) = 5.5587(8) and Fe(2)⋯Eu(1) = 5.4908(8) A (1), Fe(1)⋯G…
Slow relaxation in doped coordination polymers and dimers based on lanthanoids and anilato ligands
2019
Abstract In this work we report the synthesis, structure and magnetic properties of two lanthanoid based coordination polymers (CP) and two dimers prepared with two derivatives of the 2,5-dihydroxy-1,4-benzoquinone (C6O4X2)2− as ligands. Using the bromanilato ligand: (C6O4Br2)2− we have prepared the CP [Eu1.96Dy0.04(C6O4Br2)3(DMSO)6]·2DMSO (1) (DMSO = dimethylsulfoxide) and with the chlorocyananilato ligand: (C6O4(CN)Cl)2−) we have prepared one CP formulated as [Eu1.96Dy0.04(C6O4(CN)Cl)3(DMSO)6] (2) and two isostructural dimers: [Eu1.96Dy0.04(C6O4(CN)Cl)3(H2O)10]·6H2O (3) and [Eu2(C6O4(CN)Cl)3(H2O)10]·6H2O (4). Compounds 1, 2 and 3 are Eu(III) compounds doped with 2.0 % of Dy(III), whereas …
Field-induced slow relaxation of magnetisation in two one-dimensional homometallic dysprosium(iii) complexes based on alpha- and beta-amino acids.
2020
Two one-dimensional dysprosium(III) complexes based on α-glycine (gly) and β-alanine (β-ala) amino acids, with the formula {[Dy2(gly)6(H2O)4](ClO4)6·5H2O}n (1) and {[Dy2(β-ala)6(H2O)4](ClO4)6·H2O}n (2), have been synthesised and characterised structurally and magnetically. Both compounds crystallise in the triclinic system with the space group P. In 1, two DyIII ions are eight-coordinate and bound to six oxygen atoms from six gly ligands and two oxygen atoms from two water molecules, showing different geometries (bicapped trigonal prism and square antiprism). In 2, two DyIII ions are nine-coordinate and bound to seven oxygen atoms from six β-ala ligands and two oxygen atoms from two water m…
The yttrium chloride-1,10-phenanthroline interaction: Synthesis and X-ray crystal structure of the complex [Y(OH)(H2O)2(phen)2]2Cl4·2(phen)·MeOH
1991
Abstract Investigations on the reaction between YCl3·H2O and phen (1,10-phenanthroline) led to the isolation of the title compound. The synthesis, IR and X-ray structural characterization are described. The crystal contains centrosymmetric binuclear dications [Y2(phen)4(μ-OH)2(H2O)4]4+, uncoordinated chloride anions, two clathrated phen molecules and a disordered methanol molecule. The yttrium ions are eight-coordinated with square antiprismatic geometry to the nitrogen atoms of two phen molecules, to bridging hydroxyl groups and to two water molecules. The Y ⋯ YI separation in the dimer is 3.651(2)A˚.