Synthesis, structure, and bonding of BaTl4. Size effects on encapsulation of cations in electron-poor metal networks

The synthesis, structure, and bonding of BaTl(4) are described [C2/m, Z = 4, a = 12.408(3), b = 5.351(1), c = 10.383(2) ?, β = 116.00(3)°]. Pairs of edge-sharing Tl pentagons are condensed to generate a network of pentagonal biprisms along b that encapsulate Ba atoms. Alternating levels of prisms along c afford six more bifunctional Tl atoms about the waists of the biprisms, giving Ba a coordination number of 16. Each Tl atom is bonded to five to seven other Tl atoms and to three to five Ba atoms. There is also strong evidence that Hg substitutes preferentially in the shared edges of the Tl biprisms in BaHg(0.80)Tl(3.20) to generate more strongly bound Hg(2) dimers. Cations that are too small relative to the dimensions of the surrounding polyanionic network make this BaTl(4) structure (and for SrIn(4) and perhaps EuIn(4) as well) one stable alternative to tetragonal BaAl(4)-type structures in which cations are bound in larger hexagon-faced nets, as for BaIn(4) and SrGa(4). Characteristic condensation and augmentation of cation-centered prismatic units is common among many relatively cation- and electron-poor, polar derivatives of Zintl phases gain stability. At the other extreme, the large family of Frank-Kasper phases in which the elements exhibit larger numbers of bonded neighbors are sometimes referred to as orbitally rich.     

Sn5Ir6B2 und Sn4Ir7B3: Zinn-Iridiumboride mit eindimensionalen Ir/B-Verbänden

Sn₅Ir₆B₂ and Sn₄Ir₇B₃: Tin Iridiumborides with Onedimensional Ir/B Structural Elements Sn₅Ir₆B₂ (hexagonal, P6 2m, a = 658.97(5) pm, c = 559.19(3) pm, Z = 1, 391 reflexions, 16 parameters, R = 0.037) and Sn₄Ir₇B₃ (hexagonal, P6₃/m, a = 926.63(5) pm, c = 563.19(3) pm, Z = 2, 323 reflexions, 24 parameters, R = 0.045) were prepared by reaction of the elements. Their structures were determined by means of single crystal X-ray methods. The structure of Sn₅Ir₆B₂ may be derived from the Fe₂P type and contains columns of boron centered trigonal Ir prisms sharing their triangular faces. In the structure of Sn₄Ir₇B₃ six of these columns are connected to form a large column with hexagonal cross section. Only every second prism therein is occupied by a boron atom. In both structures these onedimensional Ir/B structural elements are embedded in a matrix of tin atoms composed of Sn-centered Sn₆ prisms twice as long as the Ir₆ prisms.     

Oligomeric Rare-Earth-Metal Halide Clusters. Three Structures Built of (Y(16)Z(4))Br(36) Units (Z = Ru, Ir)

Suitable reactions in sealed Nb tubing at 850-950 degrees C gave good yields of a family of oligomeric cluster phases that were characterized by single-crystal X-ray diffraction means. The basic Y(16)Z(4) units ( approximately &fourmacr; symmetry) can be derived from 2+2 condensation of centered Y(6)Br(12)Z-type clusters or as tetracapped truncated tetrahedra Y(16) that are centered by a large tetrahedral Z(4). These are surrounded by 36 bromine atoms which bridge edges or cap faces of the Y(16)Z(4) nuclei and, in part, bridge to metal atoms in other clusters. The principal bonding appears to be Y-Z and Y-Br, with weaker Y-Y (&dmacr; approximately 3.70 ?) and negligible Z-Z interactions. The phase Y(16)Br(20)Ru(4) (P4(2)/nnm, Z = 2; a = 11.662(1) ?, c = 16.992 (2) ?) is isostructural with Y(16)I(20)Ru(4) and with the new Sc(16)Br(20)Z(4) (Z = Fe, Os). Syntheses only in the presence of Ir and ABr-YBr(3) fluxes (A = K-Cs) produce Y(16)Br(24)Ir(4) (Fddd, Z = 8; a = 11.718(3) ?, b = 22.361(7) ?, c = 44.702(2) ?), in which the electron-richer Ir interstitials are compensated by four additional bromine atoms and altered bridging between macroclusters. Larger amounts of YBr(3) yield a third example, Y(20)Br(36)Ir(4) (Y(16)Br(24)Ir(4).4YBr(3), I4(1)a, Z = 4; a = 12.699(1) ?, c = 45.11(1) ?). Here infinite zigzag chains of YBr(6/2) octahedra that share cis edges lie between and bridge to the Y(16)Ir(4) clusters. All of these phases contain 60-electron, closed-shell macroclusters. Y(16)Br(20)Ru(4) and Y(20)Br(36)Ir(4) were found to exhibit temperature-independent (Van Vleck) paramagnetism with values typical of those found for other rare-earth-metal, zirconium, niobium, and tantalum cluster halides.     

Ternary early-transition-metal palladium pnictides Zr3Pd4P3, Hf3Pd4P3, HfPdSb, and Nb5Pd4P4

Several ternary palladium pnictides of the early transition metals have been prepared by arc-melting of the elemental metals and the binary pnictides ZrP, HfP, HfSb2, or NbP, and their structures have been determined by X-ray diffraction methods. The phosphides M3Pd4P3 (M = Zr, Hf) adopt a new structure type (Pearson symbol oP40), crystallizing in the orthorhombic space group Pnma with Z = 4 and unit cell parameters of a = 16.387(2), b = 3.8258(5), and c = 9.979(1) A for Zr3Pd4P3 and a = 16.340(2), b = 3.7867(3), and c = 9.954(1) A for Hf3Pd4P3. The antimonide HfPdSb was identified by powder X-ray diffraction (orthorhombic, Pnma, Z = 4, a = 6.754(1) A, b = 4.204(1) A, and c = 7.701(2) A) and confirmed to be isostructural to ZrPdSb, which adopts the TiNiSi-type structure. The phosphide Nb5Pd4P4 adopts the Nb5Cu4Si4-type structure, crystallizing in the tetragonal space group I4/m with Z = 2, a = 10.306(1) A, and c = 3.6372(5) A. Coordination geometries of pentacapped pentagonal prisms for the early transition metal, tetracapped distorted tetragonal prisms for Pd, and tricapped trigonal prisms for the pnicogen are found in the three structures; tetracapped tetragonal prisms for Nb are also found in Nb5-Pd4P4. In common with many metal-rich compounds whose metal-to-nonmetal ratio is equal or close to 2:1, the variety of structures formed by these ternary palladium pnictides arises from the differing connectivity of pnicogen-filled trigonal prisms. Pnicogen-pnicogen bonds are absent in these structures, but metal-metal bonds (in addition to metal-pnicogen bonds) are important interactions, as verified by extended Hückel band structure calculations on Zr3Pd4P3.     

Transformation of AeIn4 Indides (Ae=Ba, Sr) into an AeAu2In2 structure type through gold substitution

The title compounds were prepared from the elements by high-temperature solid-state synthesis techniques. X-ray structural analyses shows that BaAu2In2 (1) and SrAu2In2 (2) crystallize in a new orthorhombic structure, Pnma, Z=4 (a=8.755(2), 8.530(2) A; b=4.712(1), 4.598(1) A; c=12.368(3), 12.283(4) A, respectively). Gold substitutes for 50% of the indium atoms in the tetragonal BaIn4 and monoclinic SrIn4 parents to give this new and more flexible orthorhombic structure. The Ae atoms in this structure are contained within chains of hexagonal prisms built of alternating In and Au that have additional augmenting atoms around their waists from further condensation of parallel displaced chains. The driving forces for these structural changes are in part the shorter Au-In distances (2.72 and 2.69 A) relative to d(In-In) in the parents, presumably because of relativistic contractions with Au. Generalities about such centered prismatic building blocks and their condensation modes in these and related phases are described. Band structure calculations (EHTB) demonstrate that the two compounds are metallic, which is confirmed by measurements of the resistivity of 1 and the magnetic susceptibilities of both.     

Preparation and Crystal Structure of PrNb_5O_(14)

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Mg2Ru5B4 und Mg5Ru13B11, zwei ternäre Magnesium-Rutheniumboride mit Kanalstrukturen

Mg₂Ru₅B₄ and Mg₅Ru₁₃B₁₁, Two Ternary Magnesium Ruthenium Borides with Channel Structures The ternary borides Mg₂Ru₅B₄ and Mg₅Ru₁₃B₁₁, crystallizing in the orthorhombic space group Pbam, were prepared by reaction of the elementary components in sealed tantalum ampoules. Mg₂Ru₅B₄ (a = 1000.0(2) pm, b = 837,6(1) pm, c = 295.42(3) pm, Z = 2, R_W = 0.027 for 563 reflections) is homeotypic with Sc₂Ru₅B₄. The structure contains BRu₆-trigonal prisms, connected by faces and edges to form pentagonal channels filled with chains of magnesium atoms. Mg₅Ru₁₃B₁₁ (a = 2190.1(2) pm, b = 996.7(2) pm, c = 294.65(3) pm, Z = 2, R_W = 0.031 for 959 reflections) has a similar but so far unknown structure in which parts of the magnesium and boron atoms are disordered.     

Structures and physical properties of new semiconducting polyselenides Ba2CudeltaAg4-deltaSe5 with unprecedented linear Se(3)4- units

The title compounds were prepared from the elements in evacuated silica tubes at 650 degrees C, followed by slow cooling. Ba2Ag4Se5 forms a new structure type, space group C2/m, with a=16.189(2) A, b=4.5528(6) A, c=9.2500(1) A, beta=124.572(3) degrees, and V=561.4(1) A3 (Z=2). A maximum of 44% of the Ag atoms may be replaced with Cu atoms without changing the structure type. The crystal structure is composed of Ag4Se(5)4- layers, interconnected via the Ba2+ cations. The Ag atoms show irregular [3+1] coordination by the Se atoms, and the Ba atoms are located in capped square antiprisms formed by Se atoms. Most intriguing is the unprecedented occurrence of linear Se(3)4- units. According to the formulation (Ba2+)2(Ag+)4Se(3)4-(Se2-)2, this selenide is electron-precise with eight positive charges equalizing the eight negative charges. Electronic structure calculations indicated the presence of a band gap, as was experimentally confirmed: the electrical conductivity measurement revealed a gap of 0.6 eV for Ba2CuAg3Se5.     

Fluorination of [Os3(CO)12] and [Ir4(CO)12

Fluorination of [Os(3)CO(12)] in HF/SbF(5) affords [Os(CO)(4)(FSbF(5))(2)]. According to its crystal structure (orthorhombic, Pna2(1), a = 1590.3(3), b = 1036.6(1), c = 878.2(2) pm, Z = 4), the two SbF(6) units occupy cis positions in the octahedral environment around the Os atom. Fluorination of [Ir(4)(CO)(12)] in HF/SbF(5) produced three different compounds: (1) [Ir(4)(CO)(8)(mu-F)(2)(Sb(2)F(11))(2)] (tetragonal, P4n2, a = 1285.2(2), c = 952.9(1) pm, Z = 2). Here, two of the six edges of the Ir(4) tetrahedron in [Ir(4)CO(12)] are replaced by bridging fluorine atoms. (2) [fac-Ir(CO)(3)(FSbF(5))(2)HF]SbF(6).HF (orthorhombic, Pnma, a = 1250.6(1), b = 1340.7(2), c = 1092.6(2) ppm, Z = 4). The Ir(4) tetrahedron in Ir(4)(CO)(12) is completely broken down, but the facial Ir(CO)(3) configuration is retained. (3) [mer-Ir(CO)(3)F(FSbF(5))(2)] (triclinic, P1, a = 834.9(1), b = 86 4.9(1), c = 1060.0(1) pm, alpha = 69.173(4) degrees, beta = 77.139(4) degrees, gamma = 88.856(4) degrees, Z = 2).     

The new structure type Gd3Ni7Al14

The crystal structure of Gd₃Ni₇Al₁₄ (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two‐layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al₄Gd₂ and Al₆) are observed, the Al atoms are inside tetragonal (Ni₂Al₂Gd₄, Ni₂Al₄Gd₂, Al₄Gd₄, Ni₄Al₄ and Al₈) and pentagonal (Ni₄Al₆ and Al₁₀) prisms, while the Gd atoms are at the centres of pentagonal (Ni₄Al₆) and hexagonal (Ni₄Al₈) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd₃Ni₇Al₁₄ are similar to those of the intermetallides PrNi₂Al₃ and ZrNiAl. In all these structures, Ni‐centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three‐dimensional framework with six‐membered rings in the (001) plane in the case of the PrNi₂Al₃ and ZrNiAl types. In the case of Gd₃Ni₇Al₁₄, six‐membered rings are also observed, but only two‐thirds of the rings are interconnected via prism edges.     

Naked clusters of 56 tin atoms in the solid state

Isolated, gigantic tin clusters of 56 atoms are discovered in the ternary compound Ba(16)Na(204)Sn(310) (cubic, F(-)43m, Z = 1, a = 25.2041(8) A) made by direct fusion of the elements at 800 degrees C. The cluster, made of four face-fused pentagonal dodecahedra, has 36 pentagonal faces and 90 edges, and resembles a concave fullerene "dented" at four places. It is made of three- and four-bonded tin atoms and is "stuffed" with four barium cations, [Ba(4)@Sn(56)](36-). This is the largest main group naked cluster in the solid state besides the fullerenes. Also occurring in the structure are two other isolated clusters of tin, Sn(16-n) (n = 0, 1, 2, 3, or 4) and Sn(8).     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 581) Tetrabariumtriphosphid,Ba4P3: Darstellung und Kristallstruktur

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 58. Tetrabariumtriphosphide, Ba₄P₃: Preparation and Crystal Structure Ba₄P₃ is obtained from the elements in the molar ratio 4:3 or by reaction of Ba₃P₂ and Ba₅P₄ in the molar ratio 1:1 (steel ampoules with inner corundum crucibles; 1 490 K). The greyish black, easily hydrolysing compound crystallizes in a new structure type oP56. The structure shows two crystallographically independent dumbbells P₂^4? (d(P? P) = 225 and 232 pm) and isolated ions P^3? corresponding to (Ba²⁺)₈(P₂^4?)₄(P^3?)₄. The partial structure of the Ba atoms forms a complex network of trigonal prisms with tetrahedral and square pyramidal holes, as well as polyhedra with 14 faces (CN 10) which are icosahedron derivatives. The P^3? anions center trigonal prisms and the 14 face polyhedron. The P-atoms of the P₂^4? dumbbells center neighboring trigonal prisms with common square faces. (Pbam (no. 55); a = 1 325.4(2) pm, b = 1 256.2(2) pm, c = 1 127.3 pm; Z = 8).     

Synthesis, Crystal Structure, Fluorescent and Thermal Properties of Sodium Tridecafluorodizirconate Na5Zr2F13 Compound

1 INTRODUCTION Considerable research effort on the heavy metal fluoride glasses like barium, zirconium fluoride and a series of rare-earth fluorozirconate compounds du- ring the last two decades was initiated by the broad optical transmission window of these glasses and thereby the potential for ultralow-loss optical fi- bers[1~10]. The fluorozirconate of alkali metals was first reported in 1938[11], and most of the sodium and potassium fluorozirconates were reported amongthe 1940s and 19…     

High-level ab initio calculations for the four low-lying families of minima of (H2O)20. I. Estimates of MP2/CBS binding energies and comparison with empirical potentials

We report estimates of complete basis set (CBS) limits at the second-order M?ller-Plesset perturbation level of theory (MP2) for the binding energies of the lowest-lying isomers within each of the four major families of minima of (H(2)O)(20). These were obtained by performing MP2 calculations with the family of correlation-consistent basis sets up to quadruple zeta quality, augmented with additional diffuse functions (aug-cc-pVnZ, n=D, T, Q). The MP2/CPS estimates are -200.1 (dodecahedron, 30 hydrogen bonds), -212.6 (fused cubes, 36 hydrogen bonds), -215.0 (face-sharing pentagonal prisms, 35 hydrogen bonds), and -217.9 kcal/mol (edge-sharing pentagonal prisms, 34 hydrogen bonds). The energetic ordering of the various (H(2)O)(20) isomers does not follow monotonically the number of hydrogen bonds as in the case of smaller clusters such as the different isomers of the water hexamer. The dodecahedron lies ca. 18 kcal/mol higher in energy than the most stable edge-sharing pentagonal prism isomer. The TIP4P, ASP-W4, TTM2-R, AMOEBA, and TTM2-F empirical potentials also predict the energetic stabilization of the edge-sharing pentagonal prisms with respect to the dodecahedron, albeit they universally underestimate the cluster binding energies with respect to the MP2/CBS result. Among them, the TTM2-F potential was found to predict the absolute cluster binding energies to within <1% from the corresponding MP2/CBS values, whereas the error for the rest of the potentials considered in this study ranges from 3% to 5%.     

Crystal structure and physical properties of the new chalcogenides Ba3Cu(17-x)(S,Te)11 and Ba3Cu(17-x)(S,Te)11.5 with two different Cu clusters

The sulfide-tellurides Ba(3)Cu(17-x)(S,Te)(11) and Ba(3)Cu(17-x)(S,Te)(11.5) were synthesized from the elements in stoichiometric ratios heated to 1073 K, followed by slow cooling to 873 K over 100 h. Ba(3)Cu(17-x)(S,Te)(11) is isostructural to Ba(3)Cu(17-x)(Se,Te)(11) when [S] > [Te], space group R ?3m, with lattice dimensions of a = 12.009(1) ?, c = 27.764(2) ?, V = 3467.6(5) ?(3), for Ba(3)Cu(15.7(4))S(7.051(5))Te(3.949) (Z = 6). The structure is composed of Cu atoms forming paired hexagonal antiprisms, capped on the two outer hexagonal faces, where each Cu atom is tetrahedrally coordinated by four Q (= S, Te) atoms. The new variant is formed when [Te] > [S]; then Ba(3)Cu(17-x)(S,Te)(11.5) adopts space group Fm3?m with a = 17.2095(8) ?, V = 5096.9(4) ?(3), for Ba(3)Cu(15.6(2))S(5.33(4))Te(6.17) (Z = 8). This structure consists of eight Te-centered Cu(16) icosioctahedra per cell interconnected by cubic Cu(8) units centered by Q atoms. Electronic structure calculations and property measurements illustrate that these compounds behave as extrinsic p-type semiconductors-toward metallic behavior for the latter compound. With standard oxidation states Ba(2+), Cu(+), and Q(2-), the electron precise formulas are Ba(3)Cu(16)Q(11) and Ba(3)Cu(17)Q(11.5).     

New barium copper chalcogenides synthesized using two different chalcogen atoms: Ba2Cu(6-x)STe4 and Ba2Cu(6-x)Se(y)Te(5-y)

Ba(2)Cu(6-x)STe(4) and Ba(2)Cu(6-x)Se(y)Te(5-y) were prepared from the elements in stoichiometric ratios at 1123 K, followed by slow cooling. These chalcogenides are isostructural, adopting the space group Pbam (Z = 2), with lattice dimensions of a = 9.6560(6) ?, b = 14.0533(9) ?, c = 4.3524(3) ?, and V = 590.61(7) ?(3) in the case of Ba(2)Cu(5.53(3))STe(4). A significant phase width was observed in the case of Ba(2)Cu(6-x)Se(y)Te(5-y) with at least 0.17(3) ≤ x ≤ 0.57(4) and 0.48(1) ≤ y ≤ 1.92(4). The presence of either S or Se in addition to Te appears to be required for the formation of these materials. In the structure of Ba(2)Cu(6-x)STe(4), Cu-Te chains running along the c axis are interconnected via bridging S atoms to infinite layers parallel to the a,c plane. These layers alternate with the Ba atoms along the b axis. All Cu sites exhibit deficiencies of up to 26%. Depending on y in Ba(2)Cu(6-x)Se(y)Te(5-y), the bridging atom is either a Se atom or a Se/Te mixture when y ≤ 1, and the Te atoms of the Cu-Te chains are partially replaced by Se when y > 1. All atoms are in their most common oxidation states: Ba(2+), Cu(+), S(2-), Se(2-), and Te(2-). Without Cu deficiencies, these chalcogenides were computed to be small gap semiconductors; the Cu deficiencies lead to p-doped semiconducting properties, as experimentally observed on selected samples.     

Palladiumpnictide des Zirconiums und Hafniums mit einem Metall : Nichtmetall‐Verhältnis von 2 : 1

Palladium Pnictides of Zirconium and Hafnium with a Metal : Nonmetal Ratio of 2 : 1 The following compounds were prepared by heating the elements in the range of 800°–1100 °C and characterized by means of X‐ray single crystal methods: Zr₅Pd₉P₇ (a = 3.815(1), b = 26.319(5), c = 6.511(1) Å) and Hf₅Pd₉P₇ (a = 3.776(1), b = 26.382(7), c = 6.500(3) Å) are isotypic and crystallize in a new structure type (Amm2; Z = 2). This also applies to ZrPdAs (a = 3.887(1), b = 19.288(6), c = 6.690(2) Å; Pmmn; Z = 10), while ZrPdSb (a = 6.814(1), b = 4.289(1), c = 7.870(2) Å) forms a TiNiSi analogous structure (Pnma; Z = 4). Common feature of all structures is the tetrahedral environment of Pd by X atoms (X: P, As, Sb). The linking of the tetrahedra leads to a PdX framework with holes, in which the Zr and Hf atoms respectively are located. The non‐metal atoms have trigonal prismatic metal coordination with three additional metal atoms outside the rectangular faces of the prisms. This XMe₉ polyhedron (Me = metal) is typical for the large family of ternary pnictides with a metal : non‐metal ratio of 2 : 1.     

Excision of uranium oxide chains and ribbons in the novel one-dimensional uranyl iodates K(2)[(UO(2))3(IO(3))(4)O(2)] and Ba[(UO(2)2(IO(3))(2)O(2)](H(2)O)

The alkali metal and alkaline-earth metal uranyl iodates K(2)[(UO(2))(3)(IO(3))(4)O(2)] and Ba[(UO(2))(2)(IO(3))(2)O(2)](H(2)O) have been prepared from the hydrothermal reactions of KCl or BaCl(2) with UO(3) and I(2)O(5) at 425 and 180 degrees C, respectively. While K(2)[(UO(2))(3)(IO(3))(4)O(2)] can be synthesized under both mild and supercritical conditions, the yield increases from <5% to 73% as the temperature is raised from 180 to 425 degrees C. Ba[(UO(2))(2)(IO(3))(2)O(2)](H(2)O), however, has only been isolated from reactions performed in the mild temperature regime. Thermal measurements (DSC) indicate that K(2)[(UO(2))(3)(IO(3))(4)O(2)] is more stable than Ba[(UO(2))(2)(IO(3))(2)O(2)](H(2)O) and that both compounds decompose through thermal disproportionation at 579 and 575 degrees C, respectively. The difference in the thermal behavior of these compounds provides a basis for the divergence of their preparation temperatures. The structure of K(2)[(UO(2))(3)(IO(3))(4)O(2)] is composed of [(UO(2))(3)(IO(3))(4)O(2)](2)(-) chains built from the edge-sharing UO(7) pentagonal bipyramids and UO(6) octahedra. Ba[(UO(2))(2)(IO(3))(2)O(2)](H(2)O) consists of one-dimensional [(UO(2))(2)(IO(3))(2)O(2)](2)(-) ribbons formed from the edge sharing of distorted UO(7) pentagonal bipyramids. In both compounds the iodate groups occur in both bridging and monodentate binding modes and further serve to terminate the edges of the uranium oxide chains. The K(+) or Ba(2+) cations separate the chains or ribbons in these compounds forming bonds with terminal oxygen atoms from the iodate ligands. Crystallographic data: K(2)[(UO(2))(3)(IO(3))(4)O(2)], triclinic, space group P_1, a = 7.0372(5) A, b = 7.7727(5) A, c = 8.9851(6) A, alpha = 93.386(1) degrees, beta = 105.668(1) degrees, gamma = 91.339(1) degrees, Z = 1; Ba[(UO(2))(2)(IO(3))(2)O(2)](H(2)O), monoclinic, space group P2(1)/c, a = 8.062(4) A, b = 6.940(3) A, c = 21.67(1), beta= 98.05(1) degrees, Z = 4.     

Ca3Pd4Bi8: Kristall‐ und elektronische Struktur

Ca₃Pd₄Bi₈: Crystal and Electronic Structure Ca₃Pd₄Bi₈ (a = 10.814(4), b = 17.050(6), c = 4.149(4) Å) was prepared by heating the elements at 900 °C and investigated by single crystal X‐ray methods. The compound crystallizes in a new structure type (Pbam; Z = 2). Six Bi atoms form distorted trigonal prisms around the Pd atoms. The polyhedra share common corners, edges or faces building up a three dimensional Pd, Bi network, whose holes are occupied by Ca atoms. A special feature is a distorted octahedron of four Pd and two Bi atoms connected via short homonuclear bonds. The metallic behaviour of the compound derived from the bond lengths is discussed by LMTO band structure calculations.     

EuIrIn4 with LaCoAl4 Type Structure – Synthesis,Magnetic Properties,and 151Eu Mössbauer Spectroscopy

LaCoAl₄ type EuIrIn₄ was synthesized by induction-melting of the elements in a sealed tantalum ampoule, followed by annealing of the sample in a high-frequency or in a muffle furnace. The EuIrIn₄ structure was refined from single-crystal X-ray diffraction data: Pmma, a = 860.65(3), b = 430.33(6), c = 757.65(7) pm, wR = 0.0748, 633 F² values and 24 variables. The striking building units are iridium-centered trigonal prisms of indium atoms, distorted bcc indium cubes and a pentagonal prismatic indium coordination of the europium atoms. Within the three-dimensional [IrIn₄]^2– polyanionic network the Ir–In and In–In distances range from 260–288 pm and 306–332 pm, respectively. The divalent ground state of europium was manifested through magnetic [7.96(1) μ_B / Eu atom, T_N = 7.9(1) K] and ¹⁵¹Eu Mössbauer spectroscopic data [δ = –10.54(2) mm · s^–1; B_hf = 19.1(1) T at 6 K].