Selten-Erd-Hydrogensulfate M(HSO4)3 (M = La,Ce–Nd): Derivate des UCl3-Typs

Rare Earth Hydrogensulfates M(HSO₄)₃ (M = La, Ce–Nd): Derivatives of the UCl₃ Type of Structure Hydrogensulfates of the lighter lanthanides are obtained from the reaction of the respective anhydrous sulfates with conc. sulfuric acid at 200 °C. According to X-ray single crystal determinations on La(HSO₄)₃ (hexagonal, P6₃/m, a = 945.64(9) pm, c = 590.87(5) pm), Ce(HSO₄)₃ (a = 943.34(10) pm, c = 587.88(5) pm), Pr(HSO₄)₃ (hexagonal, P6₃/m, a = 939.8(1) pm, c = 584.82(9) pm) and Nd(HSO₄)₃ (hexagonal, P6₃/m, a = 935.67(8) pm, c = 582.36(4) pm) they all crystallize analogous to the UCl₃ type of structure with nine-coordinate M³⁺ ions. The OH groups of the [HOSO₃]^– ”︁tetrahedra”︁”︁ build up channels parallel [00.1] typical for this type of structure. Hydrogen bonding, however, is only weak in these compounds.     

New Intermetallic Compounds Ln2Ni2Mg (Ln = Y,La–Nd,Sm, Gd–Tm) with Mo2FeB2 Structure

The title compounds were synthesized by reacting the elements in sealed tantalum tubes in a high‐frequency furnace. They crystallize with the Mo₂FeB₂ structure, a ternary ordered variant of the U₃Si₂ type, space group P4/mbm. All compounds were characterized through Guinier powder patterns and the lattice parameters were obtained from least‐squares fits. Four structures were refined from single crystal X‐ray data: a = 740.5(1) pm, c = 372.5(1) pm, wR2 = 0.0430, 247 F values, 13 variables for Y₂Ni_1.90Mg, a = 764.5(1) pm, c = 394.39(9) pm, wR2 = 0.0371, 310 F values, 12 variables for La₂Ni₂Mg, a = 754.4(1) pm, c = 385.20(9) pm, wR2 = 0.0460, 295 F values, 12 variables for Pr₂Ni₂Mg, and a = 752.53(8) pm, c = 382.33(5) pm, wR2 = 0.0183, 291 F values, and 12 variables for Nd₂Ni₂Mg. A refinement of the occupancy parameters indicated small defects on the nickel site of the yttrium compound, resulting in the composition Y₂Ni_1.90Mg for the investigated single crystal. The compounds with cerium, samarium, and gadolinium to thulium as rare earth component were characterized through their Guinier powder patterns. The cell colume of Ce₂Ni₂Mg is smaller than that of Pr₂Ni₂Mg, indicating intermediate‐valent cerium. The structures can be considered as an intergrowth of distored AlB₂ and CsCl related slabs of compositions LnNi₂ and LnMg. Chemical bonding in La₂Ni₂Mg and isotypic La₂Ni₂In is compared on the basis of extended Hückel calculations.     

Synthese und Kristallstruktur von Silber(II)‐Fluoriden AgMIVF6 (MIV = Sn,Ti, Pb,Pd, Pt,Rh)

Synthesis and Crystal Structure of Silver(II) Fluorides AgM^IVF₆ (M^IV = Sn, Ti, Pb, Pd, Pt, Rh) For the first time single crystals of AgSnF₆ (light blue, triclinic with a = 519.93(7) pm, b = 524.96(10) pm, c = 563.13(9) pm, α = 115.66(2)°, β = 89.28(2)°, γ = 118.77(2)°, spcgr. P1–C ; (No. 2), Z = 1) and AgPdF₆ (brown green, triclinic with a = 501.5(2) pm, b = 508.7(2) pm, c = 996.4(2) pm, α = 89.58(2)°, β = 103.10(2)°, γ = 120.88(2)°, spcgr. P1–C , (No. 2), Z = 2) have been synthesized and investigated. Other compounds of this type, like AgTiF₆ and AgPbF₆ (isotypic to AgSnF₆) or AgPtF₆ and AgRhF₆ (isotypic to AgPdF₆) have been synthesized in form of microcrystalline powders, their lattice parameters have been determined by Guinier data. All compounds are structure variants oft the LiSbF₆‐type and isotypic with CuMF₆ (M = Ti, Sn, Pb and Pd, Pt, respectively).     

Amido-Komplexe von Mangan(II). Synthese und Kristallstrukturen von [Mn(NPh2)2(THF)]2 und Na2[Mn(NPh2)4] · 2 C7H8

Amido Complexes of Manganese(II). Syntheses and Crystal Structures of [Mn(NPh₂)₂(THF)]₂ and Na₂[Mn(NPh₂)₄] · 2 C₇H₈ The silylated amido complex [Mn{N(SiMe₃)₂}₂ · (THF)] reacts in toluene solution with diphenylamine under ligand exchange to form the diphenylamido complex [Mn(NPh₂)₂(THF)]₂ ( 1 ), which forms orange-red columnar crystals. 1 reacts in THF solution with NaN(SiMe₃)₂ and after crystallization from toluene yellow-orange Na₂[Mn(NPh₂)₄] · 2 C₇H₈ ( 2 ) is obtained. According to the crystal structure analyses the manganese atoms in 1 (space group P2₁/c, Z = 2) are linked via the N atoms of two of the NPh₂^– groups to form centrosymmetric Mn₂N₂ four-membered rings with Mn–N bonds of almost the same length. 2 (space group I4₁/a, Z = 4) forms a three-dimensional space-lattice structure, which arises from ”︁inner solvation”︁”︁ of the sodium atoms with the phenyl rings of the NPh₂^– group.     

Platinum‐Indium Polyanions in the Structures of LaPtIn4 and LnPtIn3 (Ln = La,Ce, Pr,Nd, Sm) and Structure Refinement of Ce2Pt2In

The title compounds were prepared by reacting the elements in an arc‐melting furnace and subsequent annealing. The LaRuSn₃ type structure of the new compounds LnPtIn₃ (Ln = La, Ce, Pr, Nd, Sm) was refined from single crystal X‐ray data for LaPtIn₃: Pm3n, a = 980.4(2) pm, wR2 = 0.0271, 399 F² values, 15 variables. Striking structural motifs of LaPtIn₃ are condensed distorted trigonal [PtIn₆] prisms with Pt–In distances of 269 pm. The lanthanum atoms occupy large cavities within the polyhedral network. Besides Pt–In bonding In–In bonding also plays an important role in LaPtIn₃ with In–In distances of 299 and 327 pm. The La1 position is occupied only to 91%, resulting in a composition La_0.98(1)PtIn₃. The La1 atoms show an extremely large displacement parameter indicating a rattling of these atoms in the In₁₂ cages. The so far most indium rich compound in the ternary system lanthanum‐platinum‐indium is LaPtIn₄ which was characterized on the basis of Guinier powder data: YNiAl₄‐type, Cmcm, a = 455.1(2) pm, b = 1687.5(5) pm, and c = 738.3(2) pm. The platinum atoms in LaPtIn₄ center trigonal prisms with the composition [La₂In₄]. Together with the indium atoms the platinum atoms form a complex three‐dimensional [PtIn₄] polyanion in which the lanthanum atoms occupy large hexagonal tubes. The structure of Ce₂Pt₂In is confirmed: Mo₂FeB₂‐type, P4/mbm, a = 779.8(1) pm, c = 388.5(1) pm, wR2 = 0.0466, 433 F² values, 12 parameters. It is built up from CsCl and AlB₂ related slabs with the compositions CeIn and CePt₂, respectively. Chemical bonding in the [PtIn₃] and [PtIn₄] polyanions of LaPtIn₃ and LaPtIn₄ is discussed.     

Neue Rhodiumverbindungen mit LiCo6P4‐Struktur

New Rhodium Compounds with the LiCo₆P₄ Type Structure Five new phosphides and arsenides respectively of the formula ARh₆X₄ (A: Mg–Sr, Yb; X: P, As) were prepared by heating mixtures of the elements and investigated by means of single crystal X‐ray methods. They are isotypic and crystallize in the LiCo₆P₄ type structure (P6m2; Z = 1) (lattice constants see ”︁Inhaltsübersicht”︁”︁). The compounds belong to the large family of phosphides and arsenides, which have a metal : non‐metal ratio of about 2 : 1. Their structures are characterized by the environment of phosphorus and arsenic respectively, which is composed of trigonal prisms of metal atoms with additional metal atoms capping the rectangular faces of the prisms.     

Theoretical Study of Pd11Si6 Nanosheet Compounds Including Seven‐Coordinated Si Species and Its Ge Analogues

Nanosheet compounds Pd₁₁(SiiPr)₂(SiiPr₂)₄(CNtBu)₁₀ ( 1 ) and Pd₁₁(SiiPr)₂(SiiPr₂)₄(CNMes)₁₀ ( 2 ), containing two Pd₇(SiiPr)(SiiPr₂)₂(CNR)₄ plates (R=tBu or Mes) connected with three common Pd atoms, were investigated with DFT method. All Pd atoms are somewhat positively charged and the electron density is accumulated between the Pd and Si atoms, indicating that a charge transfer (CT) occurs from the Pd to the Si atoms of the SiMe₂ and SiMe groups. Negative regions of the Laplacian of the electron density were found between the Pd and Si atoms. A model of a seven‐coordinated Si species, that is, Pd₅(Pd?SiMe), is predicted to be a stable pentagonal bipyramidal molecule. Five Pd atoms in the equatorial plane form bonding overlaps with two 3p orbitals of the Si atom. This is a new type of hypervalency. The Ge analogues have geometry and an electronic structure similar to those of the Si compounds. But their formation energies are smaller than those of the Si analogues. The use of the element Si is crucial to synthesize these nanoplate compounds.     

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.     

Preparation and Crystal Structure of Rare Earth Rhenates: the Series Ln5Re2O12 with Ln = Y,Gd–Lu,and the Praseodymium Rhenates Pr3ReO8, Pr3Re2O10, and Pr4Re2O11

The crystal structure of the known compounds Ln₅Re₂O₁₂ (Ln = Y, Gd, Dy–Lu) and the new isotypic terbium rhenate Tb₅Re₂O₁₂ was determined from X‐ray data of a twinned crystal of Ho₅Re₂O₁₂: B2/m, a = 1236.5(4) pm, b = 748.2(2) pm, c = 563.8(1) pm, γ = 107.73(3)°, Z = 2, R = 0.034 for 379 structure factors and 37 variable parameters. The rhenium atoms (oxidation number +4.5) have octahedral oxygen coordination. These ReO₆ octahedra share edges, thus forming infinite strings with alternating short and long Re–Re distances: 243.6(2) and 320.1(2) pm. Of the three holmium positions two are surrounded by seven oxygen atoms and the third one has octahedral oxygen coordination. The crystal structure of Pr₃ReO₈ was refined from single‐crystal X‐ray data: P2₁/a, a = 1498.0(2) pm, b = 749.09(8) pm, c = 610.48(9) pm, γ = 110.39(1)°, R = 0.017 for 2082 F values and 110 variable parameters. It is isotypic with a structure first determined for Sm₃ReO₈. The new compounds Pr₃Re₂O₁₀ and Pr₄Re₂O₁₁ were prepared by reaction of elemental praseodymium with the metaperrhenate Pr(ReO₄)₃. They were characterized through their X‐ray powder diagrams. Pr₃Re₂O₁₀ was found to be monoclinic: a = 778.47(9) pm, b = 773.62(9) pm, c = 706.10(8) pm, β = 114.77(1)°. It is isotypic with La₃Os₂O₁₀ and La₃Re₂O₁₀. Pr₄Re₂O₁₁ crystallizes with Nd₄Re₂O₁₁ type structure with the tetragonal lattice constants a = 1272.49(3) pm, c = 562.29(2) pm. The compounds Nd₄Re₂O₁₁ and Sm₄Re₂O₁₁ are confirmed. The magnetic properties of Ho₅Re₂O₁₂, Tb₅Re₂O₁₂, Pr₃Re₂O₁₀, Pr₄Re₂O₁₁, Nd₄Re₂O₁₁, and Sm₄Re₂O₁₁ were investigated with a Faraday balance. None of these compounds shows magnetic order above 200 K.     

CaRhIn with TiNiSi Type Structure and CaTIn2 (T = Rh,Ir) with a New Filled Version of the Zintl Phase CaIn2

CaRhIn, CaRhIn₂, and CaIrIn₂ were synthesized by reacting the elements in glassy carbon crucibles under an argon atmosphere in a high‐frequency furnace. CaRhIn adopts the TiNiSi structure: Pnma, a = 730.0(4) pm, b = 433.1(2) pm, c = 828.8(4) pm, wR2 = 0.0707, 630 F² values, 20 variables. The CaRhIn structure consists of strongly puckered Rh₃In₃ hexagons with Rh–In distances ranging from 273 to 276 pm. Due to the strong puckering each rhodium atom has a distorted tetrahedral indium environment. The calcium atoms fill the channels within the three‐dimensional [RhIn] polyanion. CaRhIn₂ and CaIrIn₂ crystallize with a new structure type: Pnma, a = 1586.2(3) pm, b = 781.4(2) pm, c = 570.9(1) pm, wR2 = 0.0385, 1699 F² values, 44 variables for CaRhIn₂, and Pnma, a = 1588.7(3) pm, b = 780.8(1) pm, c = 574.0(1) pm, wR2 = 0.0475, 1661 F² values, 44 variables for CaIrIn₂. The structures of CaRhIn₂ and CaIrIn₂ can be described as an orthorhombically distorted rhodium respectively iridium filled CaIn₂. The motif of transition metal filling is similar to that found in MgCuAl₂ type compounds CaTIn₂ (T = Pd, Pt, Au) and SrTIn₂ (T = Rh, Pd, Ir, Pt), but constitute a different tiling. Semi‐empirical band structure calculations for CaRhIn and CaRhIn₂ reveal strong bonding In–In and Rh–In but weaker Ca–Rh and Ca–In interactions. Magnetic susceptibility and resistivity measurements of compact polycrystalline samples of CaRhIn₂ indicate weak Pauli paramagnetism and metallic conductivity with a room temperature value for the specific resistivity of 230 ± 50 μΩcm.     

Darstellung und Kristallstrukturen der Verbindungen CaPdAs,CaPdSb und CaPdBi

Preparation and Crystal Structures of the Compounds CaPdAs, CaPdSb, and CaPdBi The new compounds CaPdAs, CaPdSb, and CaPdBi were prepared by heating appropriate mixtures of the elements. X-ray structure determinations carried out with single crystals (space group and lattice constants see “Inhaltsübersicht”) showed, that the arsenide crystallizes in a distorted stacking variant of the AlB₂, type structure, where the Pd atoms have a planar environment of As atoms. CaPdSb and CaPdBi are isotypic and form the TiNiSi type structure, where the Pd-Atoms are surrounded tetrahedrally (strongly distorted) by Sb or Bi atoms.     

Intermetallic Gold Compounds REAuMg (RE = Y,La–Nd,Sm, Eu,Gd–Yb)

New intermetallic rare earth compounds REAuMg (RE = Y, La–Nd, Sm, Eu, Gd–Yb) were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. Some structures were refined on the basis of single crystal data. The compounds with Y, La–Nd, Sm, and Gd–Tm adopt the ZrNiAl type structure with space group P62m: a = 770.8(2), c = 419.5(1) pm, wR2 = 0.0269, 261 F² values for PrAuMg, a = 750.9(2), c = 407.7(1) pm, wR2 = 0.0561, 649 F² values for HoAuMg with 15 variables for each refinement. Geometrical motifs in HoAuMg are two types of gold centered trigonal prisms: [Au1Mg₃Ho₆] and [Au2Mg₆Ho₃]. The gold and magnesium atoms form a three‐dimensional [AuMg] polyanion in which the holmium atoms fill distorted hexagonal channels. The magnesium positions show a small degree of magnesium/gold mixing resulting in the refined compositions PrAu_1.012(2)Mg_0.988(2) and HoAu_1.026(3)Mg_0.974(3). EuAuMg and YbAuMg contain divalent europium and ytterbium, respectively. Both compounds crystallize with the TiNiSi type structure, space group Pnma: a = 760.6(3), b = 448.8(2), c = 875.8(2) pm, wR2 = 0.0491, 702 F² values, 22 variables for EuAuMg, and a = 738.4(1), b = 436.2(1), c = 864.6(2) pm, wR2 = 0.0442, 451 F² values, and 20 variables for YbAuMg. The europium position shows a small degree of europium/magnesium mixing, and the magnesium site a slight magnesium/gold mixing leading to the refined composition Eu_0.962(3)Au_1.012(3)Mg_1.026(3). No mixed occupancies were found in YbAuMg where all sites are fully occupied. In these structures the europium(ytterbium) and magnesium atoms form zig‐zag chains of egde‐sharing trigonal prisms which are centered by the gold atoms. As is typical for TiNiSi type compounds, also in EuAuMg and YbAuMg a three‐dimensional [AuMg] polyanion occurs in which the europium(ytterbium) atoms are embedded. The degree of distortion of the two polyanions, however, is different.     

Neue thermische Abbauprodukte von Ln2CeMO6Cl3 (M = Nb,Ta; Ln = La–Sm) – Darstellung von strukturverwandtem (La, Tb)3,5TaO6Cl4–x

Contributions on the Investigation of Inorganic Nonstoichiometric Compounds. XLV. New Thermal Decomposition Products of Ln₂CeMO₆Cl₃ – Preparation of Structure‐related (La, Tb)_3.5TaO₆Cl_4–x The thermal decomposition (T £ 900–1050°C) of Ln₂CeMO₆Cl₃ (M = Nb, Ta; Ln = La, Ce, Pr, Nd, Sm) leads to the formation of two mixed‐valenced phases (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ‘‘AB”︁”︁) and (Ln, Ce)_3.5MO₆Cl_4–x (phase ‘‘BB”︁”︁) and to the formation of chlorine according to redox‐reactions between Ce⁴⁺ and Cl^–. Single crystals of both phases (Ln, Ce)_3.25MO₆Cl_3.5–x (‘‘AB”︁”︁) and (Ln, Ce)_3.5MO₆Cl_4–x (‘‘BB”︁”︁) were obtained by chemical transport reactions using both powder of Ln₂CeMO₆Cl₃ (phase ‘‘A”︁”︁) and powder of (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ‘‘AB”︁”︁) as starting materials and chlorine (p{Cl₂; 298 K} = 1 atm) or HCl (p{HCl; 298 K} = 1 atm) as transport agent. A crystal of (La, Ce)_3.25NbO₆Cl_3.5–x (”︁AB”︁”︁) (space group: C2/m, a = 35.288(1) Å, b = 5.418(5) Å, c = 9.522(1) Å, β = 98.95(7)°, Z = 4) was investigated by x‐ray diffraction methods, a crystal of (Pr, Ce)_3.5NbO₆Cl_4–x (”︁BB”︁”︁) was investigated by synchrotron radiation (λ = 0.56 Å) diffraction methods. The lattice constants are a = 18.863(6) Å, b = 5.454(5) Å, c = 9.527(6) Å, β = 102.44(3)° and Z = 4. Structure determination in the space group C2/m (No. 12) let to R1 = 0.0313. Main building units are NbO₆‐polyhedra with slightly distorted trigonally prismatic environment for Nb and chains of face‐sharing Cl₆‐octahedra along [010]. The rare earth ions are coordinated by chlorine and oxygen atoms. These main structure features confirmed the expected relation to the starting material Ln₂CeMO₆Cl₃ (phase ”︁A”︁”︁) and to (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ”︁AB”︁”︁).     

KCuMIVF7 (MIV = Zr4+, Hf 4+), ein neuer Strukturtyp

KCuM^IVF₇ (M^IV = Zr⁴⁺, Hf ⁴⁺) a New Type of Structure KCuZrF₆ (colourless, orthorhombic, Cmcm – D (No. 63); a = 829,6 pm, b = 1276,5 pm, c = 1011,6 pm, Z = 8) and KCuHfF₇ (colourless, orthorhombic, Cmcm – D (Nr. 63); a = 829,6 pm, b = 1276,5 pm, c = 1011,6 pm, Z = 8) could be prepared by heating up in a goldtube at 700 °C for 3 weeks a mixture of KF, CuF₂, and ZrF₄ or HfF₄, respectively. Both compounds crystallize isotypic in a previous unknown structure.     

Ternary Rhodium Borides A3Rh5B2 (A = Mg,Sc) and Quaternary Derivatives A2MRh5B2. Preparation,Crystal Structure (M = Main Group and 3 d Elements), and Magnetism (M = Mn,Fe)

The new ternary rhodium borides Mg₃Rh₅B₂ and Sc₃Rh₅B₂ (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti₃Co₅B₂ type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A_3–xM_xRh₅B₂ with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A₂MRh₅B₂: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti₃Co₅B₂ type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below T_N = 130 K, while Sc/Fe behaves ferromagnetically below T_C = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious.     

Synthesis of the New Silanediyldiphosphinite tBu2Si(OPPh2)2 and its Reactions with the Norbornadiene Complexes C7H8M(CO)4 (M = Cr,Mo, W). Crystal Structures of cis-M(CO)4[tBu2Si(OPPh2)2] (M = Cr,Mo)

Silanediyldiphosphinite tBu₂Si(OPPh₂)₂ 1 has been synthesised. 1 reacts with the norbornadiene complexes C₇H₈M(CO)₄ (M = Cr, Mo, W) to give six-membered chelate rings of the type cis-M(CO)₄[tBu₂Si(OPPh₂)₂] 2–4 . The crystal structures of the chromium and molybdenum complexes cis-Cr(CO)₄[tBu₂Si(OPPh₂)₂] 2 and cis-Mo(CO)₄[tBu₂Si(OPPh₂)₂] 3 have been determined. Both complexes crystallise in the triclinic system (space group P1 ) with unit cell parameters: ( 2 ) a = 1 093(3) pm, b = 1 477(5) pm and c = 1 542(5) pm; α = 108.4(2)°, b? = 103.87(11)° and b? = 104.57(10)°; U = 2.143(12) nm³; Z = 2; ( 3 ) a = 1 097.8(2) pm, b = 1 483.7(2) pm and c = 1 554.3(2) pm; α = 108.10(1)°, b? = 103.956(6)° and γ = 104.213(7)°; U = 2.1899(6) nm³; Z = 2. Both 2 and 3 consist of discrete, slightly distorted, octahedral monomers in which the six-membered chelate rings are essentially planar. In contrast, the conformations of the chelate rings found in crystal structures of analogous complexes vary from twist-boat to “chaise longue”.     

Synthese und Kristallstruktur von ACu4As2 (A: Ca–Ba,Eu)

Synthesis and Crystal Structure of A Cu₄As₂ ( A : Ca–Ba, Eu) Steel‐gray single crystals of ACu₄As₂ with A = Ca–Ba and Eu respectively were synthesized by heating mixtures of the elements at about 900 °C. Structure determinations with X‐ray diffractometry data revealed, that the isotypic compounds crystallize in the rhombohedral CaCu₄P₂ type structure (R3m; Z = 3) (hexagonal axes see ”︁Inhaltsübersicht”︁”︁). Measurements of the susceptibility of EuCu₄As₂ showed divalent Eu and ferromagnetic order at 35 K.     

Ternäre Selenide der Lanthanide mit Alkalimetallen: I. Der Formeltyp Cs3M7Se12 (M = Gd–Ho)

Ternary Selenides of the Lanthanides with Alkali Metals: I. The Composition Cs₃M₇Se₁₂ (M = Gd–Ho) When the lanthanides gadolinium, terbium, dysprosium and holmium are oxidized with selenium in a molar ratio of 2 : 3 in evacuated silica tubes (700 °C, 7 d) and CsCl is added, ternary cesium lanthanide selenides with the composition Cs₃M₇Se₁₂ (M = Gd–Ho) readily form. Surplus CsCl as flux accelerates the crystallization of the yellow, transparent needles. Since these crystals are stable to hydrolysis, excess CsCl and the chloride by-products (e. g. Cs₃MCl₆) can be rinsed off easily with water. The crystal structure of the flanking representatives Cs₃Gd₇Se₁₂ and Cs₃Ho₇Se₁₂ (orthorhombic, Pnnm (no. 58), Z = 2; Cs₃Gd₇Se₁₂: a = 1294.8(3), b = 2650.1(5), c = 419.36(9) pm, R₁ = 0.098, wR₂ = 0.173; Cs₃Ho₇Se₁₂: a = 1280.4(3), b = 2621.2(5), c = 412.13(8) pm, R₁ = 0.096, wR₂ = 0.126) was determined and refined on the basis of X-ray data from single crystals. With the help of powder diffraction Cs₃Tb₇Se₁₂ (a = 1289.4(1), b = 2640.3(2), c = 416.82(3) pm) and Cs₃Dy₇Se₁₂ (a = 1285.3(1), b = 2631.5(2), c = 414.47(3) pm) were established to be isotypic. The four new compounds crystallize isostructurally with Cs₃Y₇Se₁₂, so that a three-dimensional framework {[M₇Se₁₂]^3–} of vertex- and edge-sharing [MSe₆] octahedra is present. Wave-like, one-dimensional infinite ”︁triple-channels”︁ run through the structure along [001] which are filled with two crystallographically different Cs⁺ cations (CN(Cs1) = 7 + 1, CN(Cs2) = 6). Owing to much too close Cs⁺–Cs⁺ contacts only a semi-occupation is possible for the Cs2 position which the structure refinements inevitably prove.     

Darstellung,Struktur und magnetische Eigenschaften von Erdalkali-Mangan-Verbindungen AMnX mit A = Mg,Ca, Sr,Ba und X = Si,Ge, Sn

Preparation, Structure, and Magnetic Properties of the Alkaline Earth Manganese Compounds AMnX with A = Mg, Ca, Sr, Ba and X = Si, Ge, Sn The new compounds MgMnGe, MgMnSn, CaMnSi, CaMnSn, and SrMnSn were prepared by reaction of the elements. They crystallize tetragonally with the anti-PbFCl type structure (space group P4/nmm). The lattice constants see ”︁Inhaltsübersicht”︁”︁. Using a Faraday balance, magnetic measurements in the range 4.2 to 800 K were performed with the new substances and with the already known compounds CaMnGe, SrMnGe, and BaMnGe. They indicate metamagnetic behaviour at low temperatures. At high temperatures twodimensional magnetic interactions between the manganese atoms seem to persist. The construction of an unexpensive heating device for the Faraday balance is described.     

Two‐ and Three‐Dimensional [IrSi] Networks in the Silicides Sm3Ir2Si2, HoIrSi,and YbIrSi

New intermetallic rare earth iridium silicides Sm₃Ir₂Si₂, HoIrSi, and YbIrSi were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. HoIrSi and YbIrSi crystallize in a TiNiSi type structure, space group Pnma: a = 677.1(1), b = 417.37(6), c = 745.1(1) pm, wR2 = 0.0930, 340 F² values for HoIrSi, and a = 667.2(2), b = 414.16(8), c = 742.8(2) pm, wR2 = 0.0370, 262 F² values for YbIrSi with 20 parameters for each refinement. The iridium and silicon atoms build a three‐dimensional [IrSi] network in which the holmium(ytterbium) atoms are located in distorted hexagonal channels. Short Ir–Si distances (246–256 pm in YbIrSi) are indicative for strong Ir–Si bonding. Sm₃Ir₂Si₂ crystallizes in a site occupancy variant of the W₃CoB₃ type: Cmcm, a = 409.69(2), b = 1059.32(7), c = 1327.53(8) pm, wR2 = 0.0995, 383 F² values and 27 variables. The Ir1, Ir2, and Si atoms occupy the Co, B2, and B1 positions of W₃CoB₃, leading to eight‐membered Ir₄Si₄ rings within the puckered two‐dimensional [IrSi] network. The Ir–Si distances range from 245 to 251 pm. The [IrSi] networks are separated by the samarium atoms. Chemical bonding in HoIrSi, YbIrSi, and Sm₃Ir₂Si₂ is briefly discussed.