Syntheses and Structure of Gd<Subscript>3</Subscript>Rh<Subscript>1.940(7)</Subscript>In<Subscript>4</Subscript>

Summary. The gadolinium–rhodium–indide Gd₃Rh_1.940(7)In₄ was prepared by arc-melting of the elements and subsequent annealing in a corundum crucible in a sealed silica tube. Gd₃Rh_1.940(7)In₄ adopts the hexagonal Lu₃Co_1.87In₄ type, space group , a = 781.4(5), c = 383.8(3) pm, wR2 = 0.0285, BASF = 0.375(1) (merohedric twinning via a twofold axis (xx0)), 648 F² values, 22 variables. The structure is derived from the well known ZrNiAl type through an ordering of rhodium and indium atoms on the Ni2 sites. The Rh/In ordering forces a reduction of the space group symmetry from to , leading to merohedric twinning for the investigated crystal. The Rh1 site has an occupancy of only 94.0(7)%. The investigated crystal had a composition Gd₃Rh_1.940(7)In₄. The main geometrical motif are three types of centered, tricapped trigonal prisms, i.e., [Rh1In2₆Gd₃], [Rh2Gd₆In2₃], and [In1Gd₆In2₃]. The shortest interatomic distances occur for Rh–In (276–296 pm) followed by In–In (297 pm). Together, the rhodium and indium atoms build up a three-dimensional [Rh_1.940(7)In₄] network, in which the gadolinium atoms fill slightly distorted pentagonal channels. The crystal chemistry of Gd₃Rh_1.940(7)In₄ is discussed on the basis of a group-subgroup scheme.     

The Rare Earth Metal-Rich Indides RE 4RhIn ( RE = Gd–Tm, Lu)

The rare earth-transition metal-indides RE ₄RhIn (RE = Gd–Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. Single crystals were grown via slowly cooling of the samples. The indides were investigated via X-ray powder diffraction and several structures were refined from X-ray single crystal diffractometer data: F[`4]3mF{\bar 4}3m , a = 1370.7(9) pm, wR2 = 0.049, 428 F ² values for Gd₄RhIn, a = 1360.3(6) pm, wR2 = 0.028, 420 F ² values for Tb₄RhIn, a = 1354.5(2) pm, wR2 = 0.041, 380 F ² values for Dy₄RhIn, a = 1349.2(3) pm, wR2 = 0.029, 410 F ² values for Ho₄RhIn, a = 1342.5(5) pm, wR2 = 0.037, 403 F ² values for Er₄RhIn, a = 1337.8(3) pm, wR2 = 0.038, 394 F ² values for Tm₄RhIn with 14 variable parameters per refinement, and a = 1329.7(3) pm for Lu₄RhIn. In this new structure type, the rhodium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ prisms leads to a three-dimensional network which leaves voids that are filled by regular In₄ tetrahedra (317 pm In–In distance) in Gd₄RhIn. The indium atoms have twelve nearest neighbors (3 In + 9 RE) in icosahedral coordination. The gadolinium atoms build up a three-dimensional, adamantane-like network of condensed, face-sharing empty octahedra.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F [`4]\bar 4 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed.     

New Bimetallic Ni–Rh Carbonyl Clusters: Synthesis and X-ray Structure of the [Ni7Rh3(CO)18]3?, [Ni3Rh3(CO)13]3? and [NiRh8(CO)19]2? Cluster Anions

The reaction of the [Ni₆(CO)₁₂]²⁻ dianion with [Rh(COD)Cl]₂ (COD = cyclooctadiene) in acetone affords a mixture of bimetallic Ni–Rh clusters, mainly consisting of the new [Ni₇Rh₃(CO)₁₈]³⁻ and [Ni₈Rh(CO)₁₈]³⁻ trianions. A study of the reactivity of [Ni₇Rh₃(CO)₁₈]³⁻ led to isolation of the new [Ni₃Rh₃(CO)₁₃]³⁻ and [NiRh₈(CO)₁₉]²⁻ anions. All these new bimetallic Ni–Rh carbonyl clusters have been isolated in the solid state as tetrasubstituted ammonium salts and have been characterised by elemental analysis, X-ray diffraction studies, ESI-MS and electrochemistry. The unit cell of the [NEt₄]₃[Ni₇Rh₃(CO)₁₈] salt contains two orientationally-disordered ν₂-tetrahedral [Ni₇Rh₃(CO)₁₈]³⁻ trianions with occupancy factors of 0.75 and 0.25. Besides, their inner Ni₃Rh₃ octahedral moieties show two cis sites purely occupied by Rh atoms, two trans sites purely occupied by Ni atoms and the remaining two cis sites are disordered Ni and Rh sites with respective occupancy fraction of 0.5. At difference from the parent [Ni₇Rh₃(CO)₁₈]³⁻, the octahedral [Ni₃Rh₃(CO)₁₃]³⁻ displays an ordered distribution of Ni and Rh atoms in two staggered triangles. The [NiRh₈(CO)₁₉]²⁻ dianion adopts an isomeric metal frame with respect to that of the [PtRh₈(CO)₁₉]²⁻ congener. As a fallout of this work, new high-yield synthesis of the known [Ni₆Rh₃(CO)₁₇]³⁻ and [Ni₆Rh₅(CO)₂₁]³⁻, as well as other currently-investigated bimetallic Ni–Rh clusters have been obtained.     

Rare Earth-Rich Indides RE 5Pt2In4 ( RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu)

The isotypic indides RE ₅Pt₂In₄ (RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc-melting of the elements and subsequent annealing. They were investigated via X-ray powder diffraction. Small single crystals of Gd₅Pt₂In₄ were grown via slow cooling and the structure was refined from X-ray single crystal diffractometer data: Pbam, a = 1819.2(9), b = 803.2(3), c = 367.6(2) pm, wR ² = 0.089, 893 F ² values and 36 parameters. The structure is an intergrowth variant of distorted trigonal and square prismatic slabs of compositions GdPt and GdIn. Together the platinum and indium atoms build up one-dimensional [Pt₂In₄] networks (292–333 pm Pt–In and 328–368 pm In–In) in an AA stacking sequence along the c axis. The gadolinium atoms fill distorted square and pentagonal prismatic cages between these networks with strong bonding to the platinum atoms.     

Geometric and topological analysis of icosahedral structures of samson Mg2Zn11 (cP39) Phases, K6Na15Tl18H (cP40), and Tm3In7Co9 (cP46): Nanocluster precursors, self-assembly mechanism, and superstructure ordering

Geometric and topological analysis and 3D reconstruction of self-assembly of icosahedral structures of Samson Mg₂Zn₁₁ clusters (space group Pm[`3]Pm\bar 3, cP39, 10 compounds) and the K<sub>6</sub>Na<sub>15</sub>Tl<sub>18</sub>H and Tm<sub>3</sub>In<sub>7</sub>Co<sub>9.29</sub> structures were performed by computer methods (the TOPOS program package). The complete decomposition of the 3D graph of the crystal structures into cluster substructures showed the existence of the crystal-forming nanocluster precursor A comprising 45 atoms (A-45). The S-6 cluster spacers were identified in Mg<sub>2</sub>Zn<sub>11</sub>, and the S-7 cluster spacers were found in K<sub>6</sub>Na<sub>15</sub>Tl<sub>18</sub>H. In Tm<sub>3</sub>In<sub>7</sub>Co<sub>9.29</sub>, the S-6 and S-7 cluster spacers with the centers statistically occupying the same position were determined. The A-45, S-6 (octahedron), and S-7 (centered octahedron) clusters have symmetry [`3]m\bar 3m. The A-45 nanocluster contains an inner Zn(Zn)₁₂ template icosahedron and an external quasi-spherical shell composed of 32 atoms (deltahedron D32). A-45 is equivalent to the Bergman cluster used as the approximant of the local structure of quasicrystals. For deltahedron D32, the existence of a hierarchical structure was identified as a result of self-assembly involving two types of cyclic clusters: K-7 with an atom in the center of the sixth ring and three-atom cyclic clusters K-3. The atoms of the K-3 and K-7 clusters occupy all possible positions over the 12 vertices and 20 faces of an icosahedron and thereby form an edge net of bonds made of triangles. For the K₆(Na₁₄MTl₁₈) structures (M = Mg, An, Cd, Hg), the cluster nature of superstructure ordering of three chemically different atoms (14Na, M, and 18Tl) over 33 positions of the Zn atoms in the unit cell of the basis Mg₂Zn₁₁(Mg₆Zn₃₃) structure was considered.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed. Correspondence: Rainer P?ttgen, Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms-Universit?t Münster, Germany.     

Zusammenhang zwischen Struktur und Komplexbildungseigenschaften der C1–C6-Xanthogenate mit Hg(II)-, Cd(II)- und Zn(II)-Ionen

The thermodynamic parameters D[`(H)], D[`(G)], D[`(S)]₂₉₈\Delta \bar H, \Delta \bar G, \Delta \bar S_{298} and lg _n resp. of the reactions indicated in the title have been computed from polarographic data. The numerical values obtained are nearly independent from the xanthate used. The overall formation constants increase as follows: Zn(II)<>相似文献   

La3Pd4Zn4 and La3Pt4Zn4 with a different coloring of the Gd3Cu4Ge4-type structure

Abstract  

The intermetallic zinc compounds La₃Pd₄Zn₄ and La₃Pt₄Zn₄ were synthesized by induction melting of the elements in sealed tantalum tubes. The structures were refined from X-ray single-crystal diffractometer data: Gd₃Cu₄Ge₄ type, Immm, a = 1,440.7(5), b = 743.6(2), c = 419.5(2) pm, wR ₂ = 0.0511, 353 F ² for La₃Pd₄Zn₄; and a = 1,439.9(2), b = 748.1(1), c = 415.66(6) pm, wR ₂ = 0.0558, 471 F ² for La₃Pt₄Zn₄ with 23 variables per refinement. The palladium (platinum) and zinc atoms build up a three-dimensional polyanionic [Pd₄Zn₄] (260–281 pm Pd–Zn) and [Pt₄Zn₄] (260–279 pm Pt–Zn) network in which the lanthanum atoms fill cavities of CN 14 (6 Pd/Pt + 8 Zn for La1) and CN 12 (6 Pd/Pt + 6 Zn for La2), respectively. The copper position of the Gd₃Cu₄Ge₄ type is occupied by zinc and the two crystallographically independent germanium sites by palladium (platinum), a new coloring pattern for this structure type. Within the [Pd₄Zn₄] and [Pt₄Zn₄] the Pd2 and Pt2 atoms form Pd2–Pd2 (291 pm) and Pt2–Pt2 (296 pm) dumbbells. The structures of La₃Pd₄Zn₄ and La₃Pt₄Zn₄ are discussed with respect to the prototype Gd₃Cu₄Ge₄ and the Zintl phase Sr₃Li₄Sb₄. Temperature-dependent magnetic susceptibility measurements indicate diamagnetism for La₃Pt₄Zn₄ and Pauli paramagnetism for La₃Pd₄Zn₄.     

Rare earth-rich cadmium compounds RE 4 TCd (T = Co, Ru, and Rh) with Gd4RhIn type structure

The rare earth-rich cadmium compounds RE ₄ TCd (RE = Y, La–Nd, Sm, and Gd–Tm, Lu; T = Co, Ru, and Rh) were prepared from the elements in sealed tantalum ampoules in an induction furnace. All samples were characterized by X-ray powder diffraction. The structures of Y₄RuCd (a = 1362.5(1) pm), La₄RuCd (a = 1415.9(1) pm), Gd₄RuCd (a = 1368.8(2) pm), La₄CoCd (a = 1417.9(4) pm), Gd₄CoCd (a = 1356.1(1) pm), and Gd₄RhCd (a = 1368.7(1) pm) were refined from single crystal X-ray diffractometer data. The RE ₄ TCd compounds crystallize with the cubic Gd₄RhIn type structure, space group F ${\bar 4}The rare earth-rich cadmium compounds RE ₄ TCd (RE = Y, La–Nd, Sm, and Gd–Tm, Lu; T = Co, Ru, and Rh) were prepared from the elements in sealed tantalum ampoules in an induction furnace. All samples were characterized by X-ray powder diffraction. The structures of Y₄RuCd (a = 1362.5(1) pm), La₄RuCd (a = 1415.9(1) pm), Gd₄RuCd (a = 1368.8(2) pm), La₄CoCd (a = 1417.9(4) pm), Gd₄CoCd (a = 1356.1(1) pm), and Gd₄RhCd (a = 1368.7(1) pm) were refined from single crystal X-ray diffractometer data. The RE ₄ TCd compounds crystallize with the cubic Gd₄RhIn type structure, space group F 3m. The transition metal atoms have tricapped trigonal prismatic rare earth coordination. The trigonal prisms are condensed via common edges, forming a rigid three-dimensional network with adamantane symmetry. Voids in these networks are filled by Cd₄ tetrahedra (304 pm Cd–Cd in Gd₄CoCd) and polyhedra of the RE1 atoms. The crystal chemical peculiarities are briefly discussed. Correspondence: Rainer P?ttgen, Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms-Universit?t Münster, Correnstrasse 30, 48149 Münster, Germany.     

Heterometallic clusters with the {MoNbI8} core: The synthesis and crystal structures of (Ph4P)2[Mo5NbI8Cl6] and (4-MePyH)5[Mo5NbI8Cl6]Cl2

Heterometallic chloride complexes [Mo₅NbI₈Cl₆] ⁿ⁻ (n = 2, 3) are synthesized. The crystal structures of their salts are determined: for (Ph₄P)₂[Mo₅NbI₈Cl₆] (I), triclinic crystal system, spacegroup P [`1]\bar 1, a = 10.9886(6), b = 11.4604(5), c = 13.4343(7) ?, α = 66.124(2), β = 86.892(2), γ = 86.490(2)°, Z = 1, V = 1543.35(13) ?³; and for (4-MePyH)₅[Mo₅NbI₈Cl₆]Cl₂ (II), monoclinic crystal system, space group C2/m, a = 16.4937(4), b = 14.7335(3), c = 11.6534(3) ?, β = 99.8750(10)°, Z = 2, V = 2789.94(11) ? The geometric parameters of compounds I and II and the conditions for the formation of the complexes with the charges −2 and −3 are discussed.     

Structure and properties of Ce3Pd3Bi4, CePdBi, and CePd2Zn3

The intermetallic cerium compounds Ce₃-Pd₃Bi₄, CePdBi, and CePd₂Zn₃ were synthesized from the elements in sealed tantalum ampoules in an induction furnace. The compounds were characterized by X-ray powder and single crystal diffraction: CeCo₃B₂ type (ordered version of CaCu₅), P6/mmm, a = 538.4(4), c = 427.7(4) pm, wR2 = 0.0540, 115 F ² values, 9 variables for CePd₂Zn₃ and Y₃Au₃Sb₄ type, I [`4]{\bar 4} 3d, a = 1005.2(2) pm, w R2 = 0.0402, 264 F ² values, 9 variables for Ce₃Pd₃Bi₄, and MgAgAs type, a = 681.8(1) pm for CePdBi. The bismuthide structures are build up from three-dimensional networks of corner-sharing PdBi₄ tetrahedra with Pd–Bi distances of 281 (Ce₃Pd₃Bi₄) and 296 pm (CePdBi), respectively. The cerium atoms are located in larger voids of coordination number 12 (Ce₃Pd₃Bi₄) and 10 (CePdBi). In CePd₂Zn₃ the cerium atoms fill larger channels within the three-dimensional [Pd₂Zn₃] network with 18 (6 Pd + 12 Zn) nearest neighbors. The three compounds contain stable trivalent cerium with experimental magnetic moments of μ_eff = 2.70(2), 2.48(1), and 2.49(1) μ_B/Ce atom for CePd₂Zn₃, Ce₃Pd₃Bi₄, and CePdBi, respectively. Susceptibility and specific heat data gave no hint for magnetic ordering down to 2.1 K.     

The Rare Earth Metal-Rich Indides <Emphasis Type="Italic">RE</Emphasis><Subscript>4</Subscript>RhIn (<Emphasis Type="Italic">RE</Emphasis> = Gd–Tm,Lu)

Summary. The rare earth-transition metal-indides RE ₄RhIn (RE = Gd–Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. Single crystals were grown via slowly cooling of the samples. The indides were investigated via X-ray powder diffraction and several structures were refined from X-ray single crystal diffractometer data: , a = 1370.7(9) pm, wR2 = 0.049, 428 F ² values for Gd₄RhIn, a = 1360.3(6) pm, wR2 = 0.028, 420 F ² values for Tb₄RhIn, a = 1354.5(2) pm, wR2 = 0.041, 380 F ² values for Dy₄RhIn, a = 1349.2(3) pm, wR2 = 0.029, 410 F ² values for Ho₄RhIn, a = 1342.5(5) pm, wR2 = 0.037, 403 F ² values for Er₄RhIn, a = 1337.8(3) pm, wR2 = 0.038, 394 F ² values for Tm₄RhIn with 14 variable parameters per refinement, and a = 1329.7(3) pm for Lu₄RhIn. In this new structure type, the rhodium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ prisms leads to a three-dimensional network which leaves voids that are filled by regular In₄ tetrahedra (317 pm In–In distance) in Gd₄RhIn. The indium atoms have twelve nearest neighbors (3 In + 9 RE) in icosahedral coordination. The gadolinium atoms build up a three-dimensional, adamantane-like network of condensed, face-sharing empty octahedra.     

Rare earth metal-rich indides RE14Rh3−xIn3 (RE=Y, Dy, Ho, Er, Tm, Lu)

The rare earth (RE) metal-rich indides RE₁₄Rh_3-xIn₃ (RE=Y, Dy, Ho, Er, Tm, Lu) can be synthesized from the elements by arc-melting or induction melting in tantalum crucibles. They were investigated by X-ray diffraction on powders and single crystals: Lu₁₄Co₃In₃ type, space group P4₂/nmc, Z=4, a=961.7(1), c=2335.5(5) pm, wR2=0.052, 2047 F² values, 62 variables for Y₁₄Rh₃In₃, a=956.8(1), c=2322.5(5) pm, wR2=0.068, 1730 F² values, 63 variables for Dy₁₄Rh_2.89(1)In₃, a=952.4(1), c=2309.2(5) pm, wR2=0.041, 1706 F² values, 63 variables for Ho₁₄Rh_2.85(1)In₃, a=948.6(1), c=2302.8(5) pm, wR2=0.053, 1977 F² values, 63 variables for Er₁₄Rh_2.86(1)In₃, a=943.8(1), c=2291.5(5) pm, wR2=0.065, 1936 F² values, 63 variables for Tm₁₄Rh_2.89(1)In₃, and a=937.8(1), c=2276.5(5) pm, wR2=0.050, 1637 F² values, 63 variables for Lu₁₄Rh_2.74(1)In₃. Except Yb₁₄Rh₃In₃, the 8g Rh1 sites show small defects. Striking structural motifs are rhodium-centered trigonal prisms formed by the RE atoms with comparatively short Rh-RE distances (271-284 pm in Y₁₄Rh₃In₃). These prisms are condensed via common corners and edges building two-dimensional polyhedral units. Both crystallographically independent indium sites show distorted icosahedral coordination. The icosahedra around In2 are interpenetrating, leading to In2-In2 pairs (309 pm in Y₁₄Rh₃In₃).     

Investigation of phase transitions of a pseudo-hexagonal phase of [Rh(NH3)5Cl]2[Re6S8(CN)6]·3H2O during thermal decomposition

A general motif of the crystal structure of [Rh(NH₃)₅Cl]₂[Re₆S₈(CN)₆]·3H₂O is examined, and the cluster anions are found to form a pseudo-hexagonal sublattice. The thermal decomposition of [Rh(NH₃)₅Cl]₂[Re₆S₈(CN)₆]·3H₂O is studied, and it is shown that in helium atmosphere thermolysis occurs through the formation of intermediate amorphous phases. The final product obtained at 1200°C is a disordered single-phase solid solution of Re_0.75Rh_0.25 based on the structure of rhenium. Powder X-ray diffraction data for solid solutions in the system of Rh-Re are surveyed. It is demonstrated that the data for phases prepared by the thermal decomposition of coordination compounds better match the theoretical state diagram than the experimental one. The dependence of atomic volume on the composition of solid solutions of Re_xRh_1−x is derived. Original Russian Text Copyright ? 2007 by S. A. Gromilov, K. V. Yusenko, and E. A. Shusharina __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No.5, pp.957–962, September–October, 2007.     

Ein,altes‘ Rhodiumsulfid mit überraschender Struktur: Synthese,Kristallstruktur und elektronische Eigenschaften von Rh3S4

An ‘old' Rhodiumsulfide with surprising Structure – Synthesis, Crystal Structure, and Electronic Properties of Rh₃S₄ The reaction of rhodium with rhodium(III)‐chloride and sulfur at 1320 K in a sealed evacuated quartz glass ampoule yields silvery lustrous, air stable crystals of the rhodiumsulfide Rh₃S₄. Although a sulfide of this composition was described in 1935 a closer characterization has not been undertaken. Rh₃S₄ crystallizes in a new structure type in the monoclinic space group C2/m with a = 1029(2) pm, b = 1067(1) pm, c = 621.2(8) pm, β = 107.70(1)°. Besides strands of edge‐sharing RhS₆ octahedra which are connected by S₂ pairs (S–S = 220 pm), the crystal structure of Rh₃S₄ contains Rh₆ cluster rings in chair conformation with Rh–Rh single bond lengths of 270 pm. Both fragments are linked by common sulfur atoms. Extended Hückel calculations indicate bonding overlap for both S–S‐ and Rh–Rh‐interactions. Rh₃S₄ has a composition between the neighboring phases Rh₂S₃ and Rh₁₇S₁₅ and the structure combines typical fragments of both: RhS₆‐octahedra from Rh₂S₃ and domains of metal‐metal bonds as found in Rh₁₇S₁₅. Rh₃S₄ is a metallic conductor, down to 4.5 K the substance shows a weak, temperature independent paramagnetism.     

Bismuth flux crystal growth of RERh6P4 (RE?=?Sc, Yb, Lu): new phosphides with a superstructure of the LiCo6P4 type

Abstract  

The rhodium-rich phosphides RERh₆P₄ (RE = Sc, Yb, Lu) were synthesized from the constituent elements in bismuth fluxes and their structures were refined from X-ray single-crystal diffractometer data: P3, a = 6.968(2), c = 3.666(2) ?, wR (F ²) = 0.0481, 895 F ² for ScRh₆P₄; a = 6.971(1), c = 3.673(1) ?, wR (F ²) = 0.0614, 700 F ² for YbRh₆P₄; a = 6.971(2), c = 3.682(1) ?, wR (F ²) = 0.0828, 722 F ² for LuRh₆P₄ with 37 variables per refinement. All three crystals are twinned. The twinning and the structural relationship with the aristotype LiCo₆P₄, space group P[`6]m2P\bar 6m2 are discussed on the basis of a group–subgroup scheme. The RERh₆P₄ phosphides belong to the large number of metal-rich compounds with a metal-to-phosphorus ratio near 2:1. The isolated phosphorus atoms have trigonal prismatic metal coordination by RE and Rh atoms. The high rhodium content leads to a pronounced rhodium substructure (278–293 pm Rh–Rh in ScRh₆P₄). From a geometrical point of view, the RERh₆P₄ structures can be viewed as intergrowth variants of slightly distorted ThCr₂Si₂-related slabs as realized for KRh₂P₂.     

Densities, Specific Heat Capacities, Apparent and Partial Molar Volumes and Heat Capacities of Glycine in?Aqueous Solutions of Formamide, Acetamide, and?N,N-Dimethylacetamide at T=298.15?K and?Ambient Pressure

Apparent molar volumes (V _2,φ ) and heat capacities (C _p2,φ ) of glycine in known concentrations (1.0, 2.0, 4.0, 6.0, and 8.0 mol⋅kg⁻¹) of aqueous formamide (FM), acetamide (AM), and N,N-dimethylacetamide (DMA) solutions at T=298.15 K have been calculated from relative density and specific heat capacity measurements. These measurements were completed using a vibrating-tube flow densimeter and a Picker flow microcalorimeter, respectively. The concentration dependences of the apparent molar data have been used to calculate standard partial molar properties. The latter values have been combined with previously published standard partial molar volumes and heat capacities for glycine in water to calculate volumes and heat capacities associated with the transfer of glycine from water to the investigated aqueous amide solutions, D[`(V)]<sub>2,tr</sub><sup>o</sup>\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} respectively. Calculated values for D[`(V)]<sub>2,tr</sub><sup>o</sup>\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} are positive for all investigated concentrations of aqueous FM and AM solutions. However, values for D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} associated with aqueous DMA solutions are found to be negative. The reported transfer properties increase with increasing co-solute (amide) concentration. This observation is discussed in terms of solute + co-solute interactions. The transfer properties have also been used to estimate interaction coefficients.     

New rare earth-rich aluminides and indides with cubic Gd4RhIn-type structure

Abstract  

The series of rare earth metal (RE)-rich intermetallics RE ₄ TAl and RE ₄ TIn (T = Ru, Rh, Ir) were synthesized by induction melting of the elements in sealed tantalum tubes. These compounds crystallize with the cubic Gd₄RhIn-type structure, space group F[`4]3mF\bar{4}3m. The structures of eight crystals (including the isotypic compounds Ce₄RuMg and Ce₄RuCd) have been refined from X-ray single-crystal diffractometer data. The structures are composed of condensed RE ₆ T trigonal prisms which form a rigid network with adamantane-like topology. Large cavities within these networks are filled with empty RE ₆ octahedra and Al₄, In₄, Mg₄, or Cd₄ tetrahedra, respectively. Some of the RE ₄ TAl and RE ₄ TIn show small homogeneity ranges that result from small degrees of Al/T and In/T mixing on the 16e sites. All cerium compounds show small anomalies in the plots of the cell volumes. This is confirmed by temperature-dependent magnetic susceptibility measurements. Ce₄RuMg, Ce₄RuCd, Ce₄RuAl, and Ce₄RuIn show intermediate cerium valence and no magnetic ordering down to 3 K. Ce₄RhAl shows essentially trivalent cerium.     

Rare Earth-Rich Indides <Emphasis Type="Italic">RE</Emphasis><Subscript>5</Subscript>Pt<Subscript>2</Subscript>In<Subscript>4</Subscript> (<Emphasis Type="Italic">RE</Emphasis> = Sc,Y, La–Nd,Sm, Gd–Tm,Lu)

Summary. The isotypic indides RE ₅Pt₂In₄ (RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc-melting of the elements and subsequent annealing. They were investigated via X-ray powder diffraction. Small single crystals of Gd₅Pt₂In₄ were grown via slow cooling and the structure was refined from X-ray single crystal diffractometer data: Pbam, a = 1819.2(9), b = 803.2(3), c = 367.6(2) pm, wR ² = 0.089, 893 F ² values and 36 parameters. The structure is an intergrowth variant of distorted trigonal and square prismatic slabs of compositions GdPt and GdIn. Together the platinum and indium atoms build up one-dimensional [Pt₂In₄] networks (292–333 pm Pt–In and 328–368 pm In–In) in an AA stacking sequence along the c axis. The gadolinium atoms fill distorted square and pentagonal prismatic cages between these networks with strong bonding to the platinum atoms.