New Metal-Rich Compounds NblrSi, NblrGe, and TalrSi -Synthesis, Structure, and Magnetic Properties

2001 ◽  
Vol 56 (6) ◽  
pp. 463-468 ◽  
Author(s):  
Ratikanta Mishra ◽  
Rainer Pöttgen ◽  
Gunter Kotzyba
Keyword(s):  
Magnetic Properties ◽  
Silicon Germanium ◽  
High Frequency ◽  
Room Temperature ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Dimensional Network ◽  
Pauli Paramagnetism

AbstractThe metal-rich intermetallic compounds NblrSi, NblrGe, and TalrSi were synthesized by arc-melting of the elements and subsequent annealing in glassy carbon crucibles in a high-frequency furnace. The three compounds were investigated by X-ray diffraction on powders and single crystals: TiNiSi type, Pnma, a = 641.27(3), b = 379.48(2), c = 727.70(3) pm, wR2 = 0.0773, 430 F2 values for NblrSi, a = 645.48(3), b = 389.21(2), c = 741.11(4) pm, wR2 = 0.0981, 297 F2 values for NblrGe, and a = 638.11(3), b = 378.69(2), c = 726.78(3) pm, wR2 = 0.0887, 290 F2 values for TalrSi with 20 variables for each refinement. The iridium and silicon (germanium) atoms form a three-dimensional network of puckered Ir3Si3 and Ir3Ge3 hexagons in which the niobium (tantalum) atoms fill larger cages. Magnetic susceptibility measurements on NblrSi and TalrSi indicate Pauli paramagnetism with room temperature susceptibilities of 0.30(5)·10-9 and 0.97(5)·10-9 m3/mol, respectively.

Synthesis, Structure, and Magnetic Properties of EuAgCd and YbAgCd

2001 ◽  
Vol 56 (7) ◽  
pp. 598-603 ◽  
Author(s):  
◽  
Gunter Kotzyba ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
High Frequency ◽  
Small Difference ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Pauli Paramagnetism ◽  
Long Range Ordering ◽  
Ferromagnetic Ordering ◽  
Experimental Magnetic Moment

Abstract New intermetallic compounds EuAgCd and YbAgCd were synthesized in quantitative yield by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Both com­ pounds were investigated by X-ray diffraction on powders and single crystals: KHg2 type, Imma, a = 490.41(8), b = 771.0(1), c = 834.4(2) pm, wR2 = 0.0624, 255 F2 values, 12 variables for EuAgCd, and MgZn2 type, Pb3/mmc, a = 584.66(5), c = 946.83(9) pm, wR2 = 0.0502, 187 F2 values, 11 variables for YbAgCd. Owing to the very small difference in scattering power, no long range ordering of the silver and cadmium atoms is evident from the X-ray data, although Ag-Cd ordering is expected. The silver and cadmium atoms randomly occupy the mercury and zinc positions of the KHg2 and MgZn2 type structures, respectively. In EuAgCd the [AgCd] substructure consists of strongly puckered, orthorhombically distorted Ag3 Cd3 hexagons, while a three-dimensional network of face-and comer-sharing tetrahedra is observed in YbAgCd. The rare earth atoms fill the space between the Ag3 Cd3 hexagons (EuAgCd) or within the three-dimensional tetrahedral network (YbAgCd). Magnetic susceptibility measurements in­ dicate Pauli paramagnetism for YbAgCd and Curie-Weiss behavior above 60 K for EuAgCd with an experimental magnetic moment of 7.82(3) μB/Eu indicating divalent ytterbium and europium. Ferromagnetic ordering at Tc = 28.0(5) K is observed for EuAgCd. At 2 K and 5 T the saturation magnetization is 5.85(5) μB/Eu.

Rare Earth-rich Magnesium Compounds RE4RhMg (RE = Y, La–Nd, Sm, Gd–Tm, Lu)

2007 ◽  
Vol 62 (5) ◽  
pp. 642-646 ◽  
Author(s):  
Selcan Tuncel ◽  
Ute Ch. Rodewald ◽  
Bernard Chevalier ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
High Frequency ◽  
Three Dimensional ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Magnesium Compounds ◽  
Rare Earth Coordination ◽  
Trigonal Prismatic

Abstract The series of magnesium compounds RE4RhMg (RE = Y, La-Nd, Sm, Gd-Tm, Lu) was prepared by high-frequency melting of the elements in sealed tantalum tubes. All samples were investigated by powder X-ray diffraction. The structures with RE = Sm, Gd, Dy, Ho, and Er as rare earth metal components were refined from single crystal diffractometer data: Gd4RhIn-type, F4̄3m, Z = 16, a = 1392.1(1) pm, wR2 = 0.060, 616 F2 values, 19 variables for Sm4RhMg, a = 1380.8(2) pm, wR2 = 0.071, 530 F2 values, 19 variables for Gd4RhMg, a = 1366.9(1) pm, wR2 = 0.070, 594 F2 values, 20 variables for Dy4RhMg, a = 1355.7(2) pm, wR2 = 0.077, 578 F2 values, 20 variables for Ho3.52RhMg1.48, and a = 1355.4(2) pm, wR2 = 0.075, 559 F2 values, 20 variables for Er3.94RhMg1.06 .The rhodium atoms have slightly distorted trigonal prismatic rare earth coordination. Condensation of the RhRE6 prisms leads to a three-dimensional network which leaves large voids that are filled by regular Mg4 tetrahedra with a Mg-Mg distance of 312 pm in Sm4RhMg. The magnesium atoms have twelve nearest neighbors (3 Mg + 9 RE) in icosahedral coordination. In the structures with holmium and erbium, the RE1 positions which are not involved in the trigonal prismatic network exhibit RE1/Mg mixing. Shortest distances occur for Sm-Rh (286 pm) within the rigid three-dimensional network of condensed trigonal prisms.

Structure and optical non-linearity of PbO.2B2O3

1996 ◽  
Vol 52 (2) ◽  
pp. 260-265 ◽  
Author(s):  
D. L. Corker ◽  
A. M. Glazer
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Asymmetric Distribution ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
X Ray ◽  
Dimensional Network ◽  
Non Linear ◽  
Linear Optical ◽  
Atomic Coordinates

The crystal structure of lead tetraborate, PbO.2B2O3, has been refined using single-crystal X-ray diffraction data (Mo Kα radiation, λ = 0.71069 Å). Crystal data at room temperature: Mr = 362.43, orthorhombic, P21 nm (C 7 2v ), a = 4.251 (2), b = 4.463 (3), c = 10.860 (3) Å, V = 206.04 Å3 with Z = 2, μ = 402.6 cm−1, Dx = 5.88 Mg m−3, F(000) = 316, final R = 0.022, wR = 0.025 over 655 reflections with I > 2.5σ(I). Atomic coordinates are in general agreement with those previously reported for the isostructural compound, SrO.2B2O3, by Perloff & Block [Acta Cryst. (1966), 20, 274–279]. All the borons are tetrahedrally coordinated with a three-dimensional network formed from O atoms that are common to either two or three tetrahedra. The tetrahedra show deformation because the B—O bonds involving the two-coordinated O atoms are much shorter than those involved with three-coordinated O atoms. The Pb atoms are situated in empty tunnels running along [010] left by the network of tetrahedra. The Pb atoms display a highly asymmetric distribution of Pb—O bonding, with the five shortest bonds covering the range 2.483 (5)–2.664 (5) Å, being all situated to one side of the Pb atom. Preliminary investigations of the non-linear optical behaviour of lead tetraborate are also discussed. The results indicate that doping with barium should lead to a new non-linear optical material that is both phase-matchable and has a high optical non-linearity.

A three-dimensional cyanide-bridged heterometallic coordination polymer: poly[[diacetonitrilediaqua[μ2-3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-κ4N1,N6:N3,N4]tetra-μ-cyanido-tetracyanidodimanganese(II)molybdate(IV)] dihydrate]

2014 ◽  
Vol 70 (11) ◽  
pp. 1029-1032 ◽  
Author(s):  
Xiao-Juan Xu
Keyword(s):  
Magnetic Properties ◽  
Ir Spectroscopy ◽  
Coordination Polymer ◽  
Elemental Analysis ◽  
Room Temperature ◽  
Three Dimensional ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Investigation

A metal coordination polymer, {[Mn2Mo(CN)8(C12H8N6)(CH3CN)2(H2O)2]·2H2O}n, has been synthesized by the reaction of Mn(ClO4)2·6H2O with 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine (bptz) and (Bu3N)3[Mo(CN)8] at room temperature. The polymer was characterized by IR spectroscopy, elemental analysis and X-ray diffraction, and the magnetic properties were also investigated. The X-ray diffraction analysis reveals that the compound is a new three-dimensional coordination polymer with a PtS-type network. Magnetic investigation shows antiferromagnetic coupling between adjacent Mn2+cations.

Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

2011 ◽  
Vol 66 (8) ◽  
pp. 771-776 ◽  
Author(s):  
Trinath Mishra ◽  
Rolf-Dieter Hoffmann ◽  
Christian Schwickert ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Properties ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Structural Distortions ◽  
Dimensional Network ◽  
Subgroup Scheme

The hexagonal Laves phase Ce2RuAl3 (≡ CeRu0.5Al1.5) was synthesized by high-frequencemelting of the elements in a sealed tantalum tube and subsequent annealing. The structure was refined from single-crystal X-ray diffraction data: MgZn2 type, P63/mmc, Z = 2, a = 565.38(9), c = 888.3(1) pm, wR2 = 0.0231, 193 F2 values and 13 parameters. The 2a (0.824 Ru + 0.176 Al) and 6h (0.956 Al + 0.044 Ru) Wyckoff positions show mixed occupancies leading to the composition CeRu0.48Al1.52 for the investigated crystal. The aluminum atoms build up Kagomé networks at z = 1/4 and z = 3/4 which are connected to a three-dimensional network by the ruthenium atoms. The cerium atoms fill cavities of coordination number 16 (3 Ru + 9 Al + 4 Ce) within the [RuAl3] network. The Ce2RuAl3 sample orders ferromagnetically at TC = 8.0(1) K. The cerium-rich aluminide Ce5Ru3Al2 shows unusually short Ce-Ru distances of 253 and 260 pm for the Ce1 position as a result of intermediate cerium valence. The structural distortions are discussed on the basis of a group-subgroup scheme for Pr5Ru3Al2 (space group I213) and the superstructure variant Ce5Ru3Al2 (space group R3).

Ternary Antimonides RE2Ir3Sb4 (RE = La, Ce, Pr, Nd)

2011 ◽  
Vol 66 (8) ◽  
pp. 777-783
Author(s):  
Konrad Schäfer ◽  
Wilfried Hermes ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
High Frequency ◽  
Three Dimensional ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Static Disorder ◽  
X Ray ◽  
Coordination Numbers ◽  
Arc Melting ◽  
Covalently Bonded

The antimonides RE2Ir3Sb4 (RE = La, Ce, Pr, Nd) were synthesized by arc-melting of the elements and subsequent annealing or via high-frequency melting. The samples were characterized by X-ray powder diffraction, and the four structures were refined from single-crystal X-ray diffraction data: Pr2Ir3Sb4 type, Pnma, Z = 4, a = 1621.9(2), b = 458.60(8), c = 1099.8(1) pm, wR2 = 0.036, 1558 F2 values for La2Ir3Sb4, a = 1616.6(8), b = 456.5(2), c = 1094.8(5) pm, wR2 = 0.092, 1080 F2 values for Ce2Ir3Sb4, a = 1613.0(5), b = 454.9(2), c = 1094.1(5) pm, wR2 = 0.057, 1428 F2 values for Pr2Ir3Sb4, and a = 1609.8(6), b = 452.9(2), c = 1092.3(5) pm, wR2 = 0.052, 1472 F2 values for Nd2Ir3Sb4, with 56 parameters per refinement. The Sb1 atoms show enhanced displacement off the mirror planes at y = 1/4 and y = 3/4. A series of temperature-dependent structure refinements of Pr2Ir3Sb4 down to 90 K are indicative of static disorder. The iridium and antimony atoms build up covalently bonded three-dimensional [Ir3Sb4] networks with Ir-Sb distances ranging from 256 -269 pm (Nd2Ir3Sb4). The two crystallographically independent rare earth sites fill cavities of coordination numbers 17 (8 Ir + 9 Sb) and 15 (6 Ir + 9 Sb) within the [Ir3Sb4] polyanions. Temperature-dependent magnetic susceptibility measurements indicate a stable trivalent ground state for the cerium compound. No magnetic ordering was evident down to 3 K.

Syntheses, Structures and Photoluminescent Properties of the Two Novel Coordination Polymers [Cd(pydc)2(tu)]n and [Cd2(SO4)(nic)2(tu)1.5(H2O)2]n (pydc = Pyridine-2,3-dicarboxylate, nic = Nicotinate, tu = Thiourea)

2011 ◽  
Vol 66 (5) ◽  
pp. 459-464 ◽  
Author(s):  
Chao Xu ◽  
Sheng-Bo Liu ◽  
Taike Duan ◽  
Qun Chen ◽  
Qian-Feng Zhang
Keyword(s):  
Hydrogen Bonds ◽  
Coordination Polymers ◽  
Room Temperature ◽  
Three Dimensional ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
One Dimensional ◽  
X Ray ◽  
Dimensional Network

Two novel cadmium coordination polymers, [Cd(pydc)2(tu)]n (1) and [Cd2(SO4)(nic)2(tu)1.5 - (H2O)2]n (2) (pydc = pyridine-2,3-dicarboxylate, nic = nicotinate, tu = thiourea), have been synthesized under hydrothermal conditions and structurally characterized by X-ray diffraction analysis. 1 is a one-dimensional ladder coordination polymer in a two-dimensional network formed by hydrogen bonds. 2 consists of two kinds of Cd(II) centers in different coordination environments connected via nicotinate and sulfate to form a two-dimensional grid network integrated in a three-dimensional framework generated by hydrogen bonds. 2 shows intense fluorescent emission in the solid state at room temperature

New Indides EuAuIn2, EuPdIn4, GdRhIn2, YbRhIn4, and YbPdIn4

2000 ◽  
Vol 55 (9) ◽  
pp. 834-840 ◽  
Author(s):  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen ◽  
Vasyl’ I. Zaremba ◽  
Yaroslav M. Kalychak
Keyword(s):  
High Frequency ◽  
Three Dimensional ◽  
Melting Furnace ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Arc Melting ◽  
Indium Compounds ◽  
Host Lattices

New intermetallic indium compounds EuAuIn2, EuPdIn4, GdRhIn2, YbRhln4, and YbPdIn4 were obtained by reaction of the elements. GdRhIn2 was synthesized in an arc-melting furnace, while EuAuIn2, EuPdln4, YbRhIn4, and YbPdIn4 were prepared in sealed tantalum tubes in a high-frequency furnace. The five compounds were investigated by X-ray diffraction both on powders and single crystals. EuAuIn2 and GdRhIn2 adopt the MgCuAl2 type structure with space group Cmcm. Single crystal X-ray data yielded a = 468.1(2), b = 1105.5(4), c = 753.5(4) pm, wR2 = 0.096, 343 F2 values for EuAuIn2 and a = 435.0(1), b = 1013.3(3), c = 783.6(2) pm, wR2 = 0.042, 608 F2 values for GdRhIn2 with 16 variables for each refinement. The two structures may be described as gold or rhodium filled versions of the host lattices Euln2 and GdIn2 . The three-dimensional indium networks of EuAuIn2 and GdRhIn2 resemble the lonsdaleite structure. Both structures are built up from three-dimensional [Auln2] and [Rhln2] poly anions in which the europium and gadolinium atoms occupy distorted hexagonal tubes. The modulations of the In-In distances within the indium networks are compared with other MgCuAl2 type indides. EuPdIn4 and YbPdIn4 crystallize with the YNiAl4 type, space group Cmcm: a = 454.8(2), b = 1703.2(8), c = 738.0(3) pm, wR2 = 0.044, 501 F2 values for EuPdIn4 and a = 445.8(2), b = 1666.0(4), c = 747.3(2) pm, wR2 = 0.050, 711 F2 values for YbPdIn4 with 24 variables for each refinement. In contrast, YbRhln4 adopts the LaCoAl4 type, space group Pmma: a = 863.7(2), b = 422.5(1), c = 743.1(1) pm, wR2 = 0.051, 467 F2 values and 24 variables. EuPdIn4, YbPdlIn4, and YbRhIn4 too consist of three-dimensional [Pdln4] and [Rhln4] polyanions in which the europium and ytterbium atoms are located in distorted hexagonal and pentagonal channels. Common structural motifs of these indides are distorted bcc-like indium cubes which are compared with the structures of Y2CoIn8, YCoIn5, EuRh2ln8, and elemental indium. Chemical bonding in these indides is briefly discussed

Synthesis, Crystal Structure, Magnetic, Thermal and Fluorescent Properties of [Co(H2O)4(nia)2](suc)·(H2suc)

2010 ◽  
Vol 65 (6) ◽  
pp. 695-700 ◽  
Author(s):  
Selcuk Demir ◽  
Veysel T. Yilmaz ◽  
Jerzy Mroziński ◽  
Tadeusz Lis ◽  
Małgorzata Hołyńska
Keyword(s):  
Room Temperature ◽  
Complex Cation ◽  
Three Dimensional ◽  
Octahedral Geometry ◽  
Distorted Octahedral Geometry ◽  
X Ray Diffraction ◽  
Fluorescent Properties ◽  
X Ray ◽  
Dimensional Network ◽  
Distorted Octahedral

A new cobalt(II) complex, [Co(H2O)4(nia)2](suc)·(H2suc) [nicotinamide = nia, succinate = suc2−], has been synthesized and characterized by elemental analysis, IR, TG-DTA and single-crystal X-ray diffraction. It contains [Co(H2O)4(nia)2]2+ complex cations, uncoordinated suc2− anios and H2suc species. In the complex cation the cobalt(II) ion is coordinated by four aqua and two nia ligands in a distorted octahedral geometry. The suc2− dianion acts as a counter-ion, while H2suc is present as a molecule of solvation. A three-dimensional network is formed by O-H· · ·O and N-H· · ·O hydrogen bonds. The title complex exhibits luminescence in the solid state at room temperature. The magnetism of the complex was studied over the temperature range 1.8 - 300 K.

A thermally stable three-dimensional cobalt(II) coordination polymer based on the V-shaped ligand 4-(4-carboxyphenoxy)isophthalate

2018 ◽  
Vol 74 (9) ◽  
pp. 1032-1037 ◽  
Author(s):  
Shao-Dong Li ◽  
Li-Ping Lu ◽  
Miao-Li Zhu
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Coordination Polymer ◽  
Room Temperature ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Secondary Building Units ◽  
Point Symbol

A new cobalt(II) coordination polymer (CP), poly[[bis[μ6-4-(4-carboxylatophenoxy)benzene-1,3-dicarboxylato-κ6 O 1:O 1:O 3:O 3′:O 4:O 4′]bis(1,10-phenanthroline-κ2 N,N′)tricobalt(II)] 0.72-hydrate], {[Co3(C15H7O7)2(C12H8N2)2]·0.72H2O} n , (I), is constructed from CoII ions and 4-(4-carboxyphenoxy)isophthalate (cpoia3−) and 1,10-phenanthroline (phen) ligands. Based on centrosymmetric trinuclear [Co3(phen)2(COO)6] secondary building units (SBUs), the structure of (I) is a three-dimensional CP with a (3,6)-connected net and point symbol (42.6)2(44.62.87.102). The positions of four [Co3(phen)2(COO)6] SBUs and four cpoia3− ligands reproduce a Chinese-knot-shaped arrangement along the ab plane. (I) has been characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD) and thermostability analysis. It shows a good thermal stability from room temperature to 673 K. In addition, the temperature dependence of the magnetic properties was measured.

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