Ternäre Halogenide vom Typ A3MX6. II. Das System Ag3−xNaxYCl6: Synthese,Strukturen, Ionenleitfähigkeit

Ternary Halides of the A₃MX₆ Type. II. The System Ag_3?xNa_xYCl₆: Synthesis, Structures, Ionic Conductivity . The influence of the substitution of Ag⁺ by Na⁺ ions on the crystal structure and the ionic conductivity of Ag₃YCl₆ (stuffed LiSbF₆-type structure) has been investigated. The system Ag_3?xNa_xYCl₆ forms a complete solid solution. The stuffed LiSbF₆-type structure is stable for all compositions. For compounds with Na⁺ contents of x > 1.67, the cryolite-type structure is observed as the high-temperature form. The transition temperature decreases steadily with increasing Na⁺ content. The “end member” phase Na₃YCl₆ transforms at 243 K from the monoclinic cryolite-type structure to the stuffed LiSbF₆-type structure (trigonal, R3 ; a = 697.3(1), c = 1 868.4(14) pm, Z = 3; R = 0.094; R_w = 0.069). The crystal structures of Ag_1.3Na_1.7YCl₆ (trigonal, R3 ; a = 691.5(2), c = 1 853.7(6) pm, Z = 3; R = 0.099, R_w = 0.081) and AgNa₂YCl₆ (trigonal, R3 ; a = 691.7(1), c = 1 853.9(5) pm, Z = 3; R = 0.099, R_w = 0.064) have also been determined. Both chlorides crystallize like Ag₃YCl₆ and Na₃YCl₆-I in the stuffed LiSbF₆-type structure. The monovalent cations, Ag⁺ and Na⁺, are distributed over the five octahedral voids that are occupied by the Ag⁺ ions alone in Ag₃YCl₆. The ionic conductivity for compounds within the solid solution Ag_3?xNa_xYCl₆ decreases with increasing Na⁺ content. The values for Na₃YCl₆ (σ = 1 · 10^?6 Ω^?1 cm^?1 at T = 500 K) are by 2.5 to 3.5 orders of magnitude smaller than those for Ag₃YCl₆ (σ = 6 · 10^?4 Ω^?1 cm^?1 at T = 500 K).     

Ternäre Halogenide vom Typ A3MX6. IV. [1]. Ternäre Halogenide des Scandiums mit Natrium,Na3ScX6 (X = F,Cl, Br): Synthese,Strukturen, Ionenleitfähigkeit

Ternary Halides of the A₃MX₆ Type. IV. Ternary Halides of Scandium with Sodium, Na₃ScX₆ (X = F, Cl, Br): Synthesis, Structures, Ionic Conductivity X-ray studies on single crystals of Na₃ScF₆ and Na₃ScBr₆ show, that Na₃ScF₆ crystallizes with the cryolite type (monoclinic, P2₁/n, Z = 2, a = 560.16(9), b = 580.31(8), c = 812.1(2)pm, β = 90.720(14)°) and Na₃ScBr₆, as the only ternary bromide of the rare earth elements with sodium, in the Na₃CrCl₆ type (trigonal, P3 1c, Z = 2, a = 728.95(7), c = 1309.29(17)pm). The ionic conductivity of powder samples of Na₃ScF₆, Na₃ScBr₆ and of Na₃ScCl₆ was studied by impedance spectroscopy. Activation energies were determined as 1.22 eV, 0.80 eV and 0.71 eV for the fluoride, chloride and bromide, respectively. The differences are explained from the crystal structures and the sizes and polarizabilities of the anions.     

Synthese und Kristallstrukturen der Ternären Selten-Erd-Chloride NaMCl4 (M = Eu—Yb,Y)

Synthesis and Crystal Structures of the Ternary Rare Earth Chlorides NaMCl₄ (M = Eu—Yb, Y) Single crystals of NaErCl₄ were obtained from the melt of NaCl and ErCl₃ (1:1 molar ratio) by slow cooling. It crystallizes in the monoclinic crystal system (space group P2/c) with the structure of α-NiWO₄ with a = 632.24(9) pm, b = 759.78(9) pm, c = 674.2(1) pm, b? = 92.310(3)°, Z = 2. Two preparative routes to pure powder samples of the chlorides NaMCl₄ are described. At room temperature, these are found to be isotypic with NaErCl₄ (M = Tm—Yb; II) while the triclinic structure of NaGdCl₄ is adopted with M = Gd—Ho, Y (I). Phase transitions from one structure to the other are observed for all compounds. The transition temperatures decrease with decreasing size of the ion M³⁺.     

Synthese und Kristallstruktur der Ternären Selten-Erd-Chloride Na2MCl5 (M = Sm,Eu, Gd)

Synthesis and Crystal Structure of the Ternary Rare Earth Chlorides Na₂MCl₅ (M = Sm, Eu, Gd) Single crystals of Na₂EuCl₅ were obtained from the melt of NaCl and EuCl₃ in a 2:1.2 molar ratio by slow cooling. It crystallizes in the orthorhombic crystal system (space group Pnma) with the structure of K₂PrCl₅ with a = 1 204.0(3) pm, b = 833.9(3) pm, c = 768.2(3) pm, Z = 4. Pure powder samples of the compounds Na₂MCl₅ (M = Sm? Gd) are available by heating mixtures of the binary components below the melting point.     

Ternäre Halogenide vom Typ A3MX6. I A3YCl6 (A = K,NH4, Rb,Cs): Synthese,Strukturen, Thermisches Verhalten. Über einige analoge Chloride der Lanthanide

Ternary Halides of the A₃MX₆ Type I. A₃YCI₆ (A = K, NH₄, Rb, Cs): Synthesis, Structures, Thermal Behaviour. Some Analogous Chlorides of the Lanthanides Reaction of the trichlorides MCl₃ (M = Y, Tb? Lu) with alkali chlorides AC1 (A = K, Rb, Cs) in evacuated silica ampoules at 850?900°C yields A₃MCl₆-type chlorides. (NH₄)₃YCl₆ is obtained via the ammonium-chloride route. The crystal structure of Rb₃YCl₆ (monoclinic, C2/c (no. 15), Z = 8, a = 2583(1)pm, b = 788.9(4)pm, c = 1283.9(7)pm, p = 99.63(4)°, R = 0.062, R_w = 0.050) is that of Cs₃BiCl₆. The Rb₃YCl₆/Cs₃BiCl₆ structure and the closely related structures of K₃MoCl₆ and In₂CI₃ are derived from the elpasolite-type of structure (K₂NaAlF₆) making use of the model of closest-packed layer structures. Cell parameters for the chlorides Rb₃MCl₆ (M = Y, Tb? Lu) and Cs₃YCl₆ and Cs₃ErCl₆ as well, which are all isostructural with Rb₃YCl₆, are given. The “system” (K, NH₄, Rb, Cs)YCl₆ has been investigated by DTA and high-temperature X-ray powder diffractometry.     

Ternäre Halogenide vom Typ A3MX6. VI [1]. Ternäre Chloride der Selten-Erd-Elemente mit Lithium,Li3MCl6 (M  Tb?Lu,Y, Sc): Synthese,Kristallstrukturen und Ionenbewegung

Ternary Halides of the A₃MX₆ Type. VI. Ternary Chlorides of the Rare-Earth Elements with Lithium, Li₃MCl₆ (M ? Tb? Lu, Y, Sc): Synthesis, Crystal Structures, and Ionic Motion Single crystal X-ray studies on the ternary chlorides Li₃ErCl₆, Li₃YbCl₆ and Li₃ScCl₆ show that they crystallize in three different structure types. Li₃ErCl₆ (trigonal, P3 ml, Z = 3, a = 1117.7(2); c = 603.6(2) pm; the chlorides with M ? Tb? Tm, Y are isotypic) and Li₃YbCl₆ (orthorhombic, Pnma, Z = 4, a = 1286.6(1); b = 1113.2(1); c = 602.95(8) pm; Li₃LuCl₆ is isotypic) have very similar structures that may be derived from hexagonal closest packings of chloride ions with the cations occupying octahedral holes in part statistically. Li₃ScCl₆ (monoclinic, C2/m, Z = 2, a = 639.8(1); b = 1104.0(2); c = 639,1(1) pm; β = 109.89(1)°) crystallizes isotypic with Na₃GdI₆ and Li₃ErBr₆, structures that may be derived from a cubic closes packings of anions. The ionic movement in Li₃YCl₆ and Li₃YbCl₆ has been investigated by impedance and ⁷Li-NMR spectroscopy.     

Ternäre Halogenide der Seltenen Erden vom Typ A2MX5 (A = K,In, NH4, Rb,Cs; X = Cl,Br, I)

Ternary Rare-Earth Halides of the A₂MX₅ Type (A = K, In, NH₄, Rb, Cs; X = Cl, Br, I) Ternary rare-earth (=M) chlorides, bromides, and iodides In₂MCl₅, (NH₄)₂MCl₅, Rb₂MCl₅, Cs₂MCl₅, CsRbMCl₅, K₂MBr₅, Rb₂MBr₅, K₂MI₅, and Rb₂MI₅ have been synthesized. Single crystals of In₂PrCl₅, Rb₂PrCl₅, K₂PrBr₅, and K₂PrI₅ were grown and the structures refined. The other halides were characterized by x-ray powder patterns. They are isotypic either with K₂PrCl₅(orthorhombic, Pnma, Z = 4, hexagonal arrangement of chains of edge-connected polyhedra [PrX₇]) or with Cs₂DyCl₅ (orthorhombic, Pbnm, Z = 4, hexagonal arrangement of cis-corner-connected octahedra [DyCl₆]) which may be discriminated in structure field diagrams. The thermal expansion was investigated für Cs₂LuCl₅ and Rb₂PrX₅ (X = Cl, Br, I).     

Ternäre Halogenide vom Typ A3MX6. VII [1]. Die Bromide Li3MBr6 (M=Sm?Lu,Y): Synthese,Kristallstruktur, Ionenbeweglichkeit

Ternary Halides of the A₃MX₆Type. VII. The Bromides Li₃MBr₆ (M=Sm? Lu, Y): Synthesis, Crystal Structure, and Ionic Mobility The bromides Li₃MBr₆ (M=Sm? Lu, Y) are obtained from the binary components LiBr and MBr₃. They crystallize with a substitution/addition variant of the AlCl_3? type of structure as was established from single crystal X-ray diffraction data for Li₃ErBr₆ (monoclinic, C2/m, Z = 2, a = 689.0(3), b = 1191.6(9), c = 684.2(6) pm, β = 109.77(6)°) and by powder X-ray diffraction for the remaining bromides. They are isotypic with Na₃GdI₆ and Li₃ScCl₆, respectively. Impedance spectroscopy and ⁷Li-NMR spectroscopy show that the lithium ions are highly mobile.     

Neue Halogenozinkate(II) MZnX4 (MI = Li,Na; X = Cl,Br) mit Olivinstruktur

New Halogenozincates M ZnX₄ (M^I = Li, Na; X = Cl, Br) of Olivine Type The hitherto unknown tetrabromozincates Li₂ZnBr₄ and Na₂ZnBr₄ have been prepared. Quaternary halides Li₂Zn(Cl, Br)₄ and Li₂Zn(Br, I)₄ have been not obtained due to decomposition to mixtures of LiCl and ZnBr₂, and LiBr and ZnI₂. The crystal structures of the olivine-type bromides and of the high-temperature polymorph of Li₂ZnCl₄ have been determined by neutron powder diffraction using the Rietveld method (space group Pnma, Z = 4, a = 1 360.41(4), b = 788.47(2), c = 647.07(2) pm, R_I = 9.07% (Li₂ZnBr₄), a = 1 446.32(5), b = 853.02(3), c = 676.61(2) pm, R_I = 9.29% (Na₂ZnBr₄), a = 1 277.60(3), b = 741.76(2), c = 611.10(1) pm, R_I = 7.63% (Li₂ZnCl₄)). The Raman spectra as well as the results of thermal analyses (DSC) and conductivity measurements (impedance spectroscopy) are presented and discussed. Contrary to Li₂ZnCl₄, Li₂ZnBr₄ and Na₂ZnBr₄ do not undergo any phase transition between 20°C and their melting points.     

Ternäre Bromide und Iodide zweiwertiger Lanthanide und ihre Erdalkali-Analoga vom Typ AMX3 und AM2X5

Ternary Bromides and Iodides of Divalent Lanthanides and Their Alkaline-Earth Analoga of the Type AMX₃ and AM₂X₅ Metallothermic reduction of the tribromides and -iodides MX₃ (M = Sm, Dy, Tm, Yb) with alkali metals as well as with indium and thallium (A = Cs, Rb, K, In, Tl) results in most cases in ternary compounds with the composition AMX₃ and AM₂X₅, respectively. Analogous compounds with M = Ba, Sr, Ca were synthesized from the binary components. The AMX₃ compounds crystallize with the following types of structure: the perovskite-type and its distorted variants, the NaNbO₃-II- and the GdFeO₃-type, the NH₄CdCl₃- and the stuffed PuBr₃-type. These structure types differ by a gain of condensation of the [MX₆] octahedra (three-dimensional connection via corners within the variants of the perovskite-type, double chains of edge- and face-connected octahedra within the NH₄CdCl₃-type, and layers of corner- and edge-connected octahedra within the stuffed PuBr₃-type of structure). This comes along with a reduction of the coordination number of A⁺ from 12 (“ideal” perovskite) to 8 + 2 (GdFeO₃-type), 9 (NH₄CdCl₃-type), and 8 (stuffed PuBr₃-type). Thus, the A/[MX₆] size ratio determines which AMX₃ type of structure is adopted. If the M²⁺ ion is large enough, ternary compounds with the composition AM₂X₅ occur either in addition to the AMX₃ compounds or exclusively. They crystallize with the TlPb₂Cl₅ type of structure (C.N.(M²⁺) = 7 and 8). All of the AMX₃ and AM₂X₅ compounds are summarized in a structure field diagram.     

Einkernige und zweikernige Kupfer(I)‐Komplexe vom Typ LCuCl,LCu2Cl2 und LCu2ClX [L = P(C6H4CH2NMe2)3; X = Br,I]

The title compounds 3‐5 are accessible by treatment of P(C₆H₄CH₂NMe2)₃( 1 ) with CuX ( 2a : X = Cl, 2b : X = Br, 2c : X = I) in the ratio of 1:1 or 1:2 in very good yields. Reaction of 1 with equimolar amounts of 2a affords the copper(I) chloride [P(C₆H₄CH₂NMe2)₃]CuCl ( 3 ). With a further equivalent of 2a homobimetallic [P(C₆H₄CH₂NMe2)₃]Cu₂Cl₂ ( 4 ) is formed, which also can be synthesized by the reaction of 1 with two equivalents of 2a. Complex 3 reacts with CuX (X = Br, I)to afford [P(C₆H₄CH₂NMe2)₃]Cu₂ClX ( 5a : X = Br; 5b : X = I) in which mixed halides are present. The newly synthesized complexes 3‐5 were characterized by elemental analyses, by their IR‐, ¹H‐, ¹³C{¹H}‐ and ³¹P{¹H}‐NMR spectra as well as by mass spectrometrical studies. The solid‐state structures of complexes 3 and 4 are reported. Mononuclear 3 crystallizes in the monoclinic space group P2₁/c with the cell parameters a = 14.285(2), b = 10.853(2), c = 17.425(2) Å , β = 103.310(10)?, V = 2628.9(7) Å ³ and Z = 4 with 4053 observed unique reflections; R₁ = 0.0314. The crystal structure of 3 consists of monomeric molecules with planar coordinated copper(I) centres (CuClNP). Homobimetallic 4 crystallizes in the monoclinic space group P2₁/n with a = 23.905(4), b = 10.874(3), c = 25.314(5), β = 99.130(10)?, V = 6497(2) /Aring; ³ and Z = 4 with 9021 observed unique reflections; R₁ = 0.0480. In 4 one of two copper(I) centres possesses a distorted trigonal‐pyramidal environment, while the other one is almost square‐pyramidal coordinated. The Cu₂Cl₂ segment resembles to a building block which is set up by a contact ion pair consisting of Cu⁺ and [CuCl₂]^‐ , respectively.     

Neue schnelle Ionenleiter vom Typ MMIIICl6 (MI = Li,Na, Ag; MIII = In,Y)

Novel Fast Ion Conductors of the Type M M^IIICl₆ (M^I = Li, Na, Ag; M^III = In, Y) The ternary chlorides Li₃InCl₆, Na₃InCl₆, Ag₃InCl₆, and Li₃YCl₆ have been studied by difference scanning calorimetry, high-temperature X-ray, infrared, and high-temperature Raman methods. Impedance spectroscopic measurements exhibit fast ionic conductivity increasing in the sequence Na₃InCl₆ < Li₃YCl₆ < Ag₃InCl₆ < Li₃InCl₆. In the range of 300°C, Li₃InCl₆ is the best lithium ion conductor known so far (σ = 0,2 Ω^?1 cm^?1 at 300°C). With the exception of Na₃InCl₆, the chlorides exhibit complicated order-disorder phase transitions.     

Tetramethylcyclotetraarsoxane Bridged Copper(I) Halides with Porous Sheet and Framework Structures [CuX{cyclo-(MeAsO)4}] (X=Cl,Br, I) and [Cu3X3{cyclo-(MeAsO)4}2] (X=Cl,Br)

Open sheet and framework structures [CuX{cyclo-(MeAsO)₄}] (X=Cl, Br, I) 1 – 3 and [Cu₃X₃{cyclo-(MeAsO)₄}₂] (X=Cl, Br) 4 and 5 may be prepared by self-assembly from CuX and methylcycloarsoxane (MeAsO)_n in acetonitrile solution. 1 – 3 exhibit 4⁴ nets in which (CuX)₂ units are connected through μ-1 _KAs¹ : 2 _KAs³ coordinated (MeAsO)₄ ligands into large 28-membered rings. In contrast, adjacent [CuX] chains in 4 and 5 are connected into sheets by μ₄-K⁴ As coordinated (MeAsO)₄ building blocks, with μ-1 _KAs¹ : 2 _KAs³ bridging of these layers by independent (MeAsO)₄ cyclotetramers leading to the generation of a porous framework structure. 1 – 5 were characterised by X-ray structural analysis.     

Modified Tellurium Subhalides in the New Structure Type [Te15X4]n[MOX4]2n (M = Mo,W; X = Cl,Br)

The reactions of Te₂Br with MoOBr₃, TeCl₄ with MoNCl₂/MoOCl₃, and Te with WBr₅/WOBr₃ yield black, needle-like crystals of [Te₁₅X₄][MOX₄]₂ (M = Mo, W; X = Cl, Br). The crystal structure determinations [Te₁₅Br₄][MoOBr₄]₂: monoclinic, Z = 1, C2/m, a = 1595.9(4) pm, b = 403.6(1) pm, c = 1600.4(4) pm, β = 112.02(2)°; [Te₁₅Cl₄][MoOCl₄]₂: C2/m, a = 1535.3(5) pm, b = 402.8(2) pm, c = 1569.6(5) pm, β = 112.02(2)°; [Te₁₅Br₄][WOBr₄]₂: C2, a = 1592.4(4) pm, b = 397.5(1) pm, c = 1593.4(5) pm, β = 111.76(2)° show that all three compounds are isotypic and consist of one-dimensional ([Te₁₅X₄]²⁺)_n and ([MOX₄]^?)_n strands. The structures of the cationic strands are closely related to the tellurium subhalides Te₂X (X = Br, I). One of the two rows of halogen atoms that bridges the band of condensed Te₆ rings is stripped off, and additionally one Te position has only 75% occupancy which leads to the formula ([Te₁₅X₄]²⁺)_n (X = Cl, Br) for the cation. The anionic substructures consist of tetrahalogenooxometalate ions [MOX₄]^? that are linked by linear oxygen bridges to polymeric strands. The compounds are paramagnetic with one unpaired electron per metal atom indicating oxidation state M^v, and are weak semiconductors.     

Chalkogenohalogenogallate(III) und -indate(III): Eine neue Verbindungsklasse in der dritten Hauptgruppe. Synthese und Struktur von [Ph4P]2[In2SX6], [Et4N]3[In3E3Cl6] · MeCN und [Et4N]3[Ga3S3Cl6] · THF (X = Cl,Br; E = S,Se)

Chalcogenohalogenogallates(III) and -indates(III): A New Class of Compounds for Elements of the Third Main Group. Preparation and Structure of [Ph₄P]₂[In₂SX₆], [Et₄N]₃[In₃E₃Cl₆] · MeCN and [Et₄N]₃[Ga₃S₃Cl₆] · THF (X = Cl, Br; E = S, Se) [In₂SCl₆]^2?, [In₂SBr₆]^2?, [In₃S₃Cl₆]^3?, [In₃Se₃Cl₆]^3?, and [Ga₃S₃Cl₆]^3? were synthesised as the first known chalcogenohalogeno anions of main group 3 elements. [Ph₄P]₂[In₂SCl₆] ( 1 ) (P1 ; a = 10.876(4) Å, b = 12.711(6) Å, c = 19.634(7) Å, α = 107.21(3)°, β = 96.80(3)°, γ = 109.78(3)°; Z = 2) and [Ph₄P]₂[In₂SBr₆] ( 2 ) (C2/c; a = 48.290(9) Å, b = 11.974(4) Å, c = 17.188(5) Å, β = 93.57(3)°, Z = 8) were prepared by reaction of InX₃, (CH₃)₃SiSSi(CH₃)₃ and Ph₄PX (X = Cl, Br) in acetonitrile. The reaction of MCl₃ (M = Ga, In) with Et₄NSH/Et₄NSeH in acetonitrile gave [Et₄N]₃[In₃S₃Cl₆] · MeCN ( 3 ) (P2₁/c; a = 17.328(4) Å, b = 12.694(3) Å, c = 21.409(4) Å, β = 112.18(1)°, Z = 4), [Et₄N]₃[In₃Se₃Cl₆] · MeCN ( 4 ) (P2₁/c; a = 17.460(4) Å, b = 12.816(2) Å, c = 21.513(4) Å, β = 112.16(2)°, Z = 4), and [Et₄N]₃[Ga₃S₃Cl₆] · THF ( 5 ) (P2₁/n; a = 11.967(3) Å, b = 23.404(9) Å, c = 16.260(3) Å, β = 90.75(2)°, Z = 4). The [In₂SX₆]^2? anions (X = Cl, Br) in 1 and 2 consist of two InSX₃ tetrahedra sharing a common sulfur atom. The frameworks of 3, 4 and 5 each contain a six-membered ring of alternating metal and chalcogen atoms. Two terminal chlorine atoms complete a distorted tetrahedral coordination sphere around each metal atom.     

Neue ternäre Phosphide und Arsenide des Caesiums mit Elementen der 8. Nebengruppe

New Ternary Phosphides and Arsenides of Cesium and Element of the 8th Transition Metal Group In the ternary systems Cesium/8^th transition metal group/5^th main group some new compounds were found and investigated. By single crystal measurements CsRh₂P₂ was found to crystallize in the space group 14/mmm with the lattice constants a = 390.11 pm and c = 1429.36 pm. The new compounds with the formula CsM₂X₂ (M = Fe, Co, Ru, Rh, Ir; X = P or As) crystallize in the ThCr₂Si₂-type structure, compounds of the formula Cs₂MX₂ (M = Ni, Pd, Pt; X = P or As) can be placed in a line with the K₂PdP₂-type structure.     

Zur Synthese und Kristallstruktur der ternären Carbide Na2PdC2 und Na2PtC2

Syntheses and Crystal Structures of Ternary Carbides Na₂PdC₂ and Na₂PtC₂ Na₂PdC₂ and Na₂PtC₂ were synthesized by the reaction of sodium carbide with palladium and platinum respectively. The crystal structures could be solved from X-ray powder diffraction data (space group: P3 m1, Z = 1). Both compounds crystallize in a new structure type with [M(C₂)_2/2^2?] chains (M?Pd, Pt) as the characteristic structural unit. The existence of a C? C triple bond was confirmed by Raman spectroscopy.     

Synthese,Struktur und Thermolyse von NH4[Re3Br10]

Synthesis, Structure and Thermolysis of NH₄[Re₃Br₁₀] NH₄[Re₃Br₁₀] crystallizes as dark brown single crystals upon slow cooling of a hot, saturated hydrobromic-acid solution of [Re₃Br₉(H₂O)₂] after the addition of NH₄Br. The crystal structure (monoclinic, C2/m (Nr. 12); Z = 4; a = 1461.6(7), b = 1 085.6(4), c = 1030.3(7) pm, β = 92.63(4)°, V_m = 245.9(4)cm³/mol; R = 0.097, R_w = 0.043) contains [Re₃Br₁₂]^? units that share two common edges. These chains run along [010] and are held together by NH₄⁺ ions. Each NH₄⁺ is surrounded by eight Br^? from four different chains. The first step of the thermal decomposition at 290°C is the disproportionation to ReBr₃ (ReCl₃ type), rhenium metal and (NH₄)₂[ReBr₆]. Secondly, the internal reduction of (NH₄)₂[ReBr₆] at 390°C to rhenium metal takes place.     

Ternäre Thalliumplatin- und Thalliumpalladiumchalkogenide Tl2M4X6. Synthesen,Kristallstruktur und Bindungsverhältnisse

Ternary Thallium Platinum and Thallium Palladium Chalcogenides Tl₂M₄X₆. Syntheses, Crystal Structures, and Bonding Relations The compounds Tl₂Pt₄S₆, Tl₂Pt₄Se₆, Tl₂Pt₄Te₆ and Tl₂Pd₄Se₆ can be synthesized by a melting reaction from the elements or by the reaction of thallium carbonate, transition metal powder and chalcogen powder in the temperature range between 400°C and 950°C. X-Ray investigations on single crystals and powdered samples revealed a new structure type for the compounds, that can be understood as stacking variant of the already known atom arrangement of the alkaline metal platinum chalkogenides A₂Pt₄X₆ (A ? alkaline metal, X ? S, Se). The short distances thallium-platinum and thallium-palladium, respectively, as well as the results of Extended-Hückel-calculations indicate covalent bonds between the main group and transition metal atoms.     

Neue ternäre Verbindungen des Caesiums mit Elementen der 8. Nebengruppe und 5. Hauptgruppe

New Ternary Compounds of Cesium and Elements of the 8^th Transition Metal Group and the 5^th Main Group In the ternary systems Cesium/element of the 8^th transition metal group/element of the 5^th main group some new compounds were found and investigated. Compounds of the formula Cs₂MX₂ (M = Pt, Pd, Ni; X = P, Sb, Bi) can be placed in a line with the K₂PdP₂-type structure. The new compound with the formula CsFe₂Sb₂ crystallizes in the ThCr₂Si₂-type structure. By single crystal measurements CsFe₂As₂ was found to crystallize in the space group I4/mmm with the lattice constants a = 389.43 pm and c = 1 509.97 pm.