Zum Mechanismus des thermischen Abbaus von Ammonium- und Ammin-Chlorokomplexen des Rutheniums,Rhodiums, Palladiums und Platins

On the Mechanism of the Thermal Decomposition of Ammonium and Ammin Chloro Complexes of Ruthenium, Rhodium, Palladium and Platinum The thermolysis of noble metal compounds was investigated by a combination of independent physical (DTA/TG, high-temperature Guinier-Simon-technique) and preparative methods, characterization of the educts, intermediats and products by Guinier X-ray patterns and IR spectroscopy:

• (a) (NH₄)₂[PtCl₆], (NH₄)₂[PtCl₄], [Pt(NH₃)₄][PtCl₄], [Pt(NH₃)₄]Cl₂, and trans-[Pt(NH₃)₂Cl₂];
• (b) (NH₄)₂[PdCl₄], [Pd(NH₃)₄]Cl₂, trans-[Pd(NH₃)₂Cl₂], and [Pd(NH₃)₄][PdCl₄];
• (c) (NH₄)₂[RhCl₅(H₂O)], (NH₄)₃[Rh₂Cl₉], K₂[RhCl₅(H₂O)], and K₂[RhCl₅(NH₃)];
• (d) (NH₄)₂[RuCl₅(NH₃)] and (NH₄)₄[Ru₂Cl₁₀O]

. The most important step of the mechanism of the thermal decomposition is the ?internal”? redox reaction between the noble metal cation and the nitrogen atom of the ammine ligand.     

Synthese und Struktur von Ammin- und Amidokomplexen des Iridiums

Synthesis and Structure of Ammine and Amido Complexes of Iridium The reaction of (NH₄)₂[IrCl₆] with NH₄Cl at 300 °C in a sealed glass ampoule yields the iridium(III) ammine complex (NH₄)₂[Ir(NH₃)Cl₅], which crystallizes isotypically with K₂[Ir(NH₃)Cl₅] in the orthorhombic space group Pnma with Z = 4, and a = 1350.0(2); b = 1028.5(3); c = 689.6(2) pm. The reaction of (NH₄)₂[IrCl₆] with NH₃ at 300 °C, however, gives the already known [Ir(NH₃)₅Cl]Cl₂ beside a small amount of [Ir(NH₃)₄Cl₂]Cl₂. In pure form [Ir(NH₃)₅Cl]Cl₂ is obtained by ammonolysis of (NH₄)₂[Ir(NH₃)Cl₅] at 300 °C with NH₃. [Ir(NH₃)₄Cl₂]Cl₂ crystallizes triclinic (P1, Z = 1, a = 660,2(3); b = 680,4(3); c = 711,1(2) pm; α = 103,85(2)°, β = 114,54(3)°, γ = 112,75(2)°). The structure contains Cl^– anions and [Ir(NH₃)₄Cl₂]²⁺ cations with a trans position of the Cl atoms. Upon reaction of [Ir(NH₃)₅Cl]Cl₂ with Cl₂ one ammine ligand is eliminated yielding [Ir(NH₃)₄Cl₂]Cl, which is transformed to orthorhombic [Ir(NH₃)₄(OH₂)Cl]Cl₂ (Pnma, Z = 4, a = 1335,1(3); b = 1047,9(2); c = 673,4(2) pm) by crystallization from water. In the octahedral complex [Ir(NH₃)₄(OH₂)Cl]²⁺ the four ammine ligands have an equatorial position, whereas the Cl atom and the aqua ligand are arranged axial. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Cl₂ at 330 °C affords the tetragonal Ir^IV complex (NH₄)[Ir(NH₃)Cl₅] (P4nc, Z = 2, a = 702.68(5); c = 912.89(9) pm). Its structure was determined using the powder diagram. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Br₂ in water, on the other hand, gives (NH₄)₂[IrBr₆] crystallizing in the K₂[PtCl₆] type. Oxidation of (PPh₄)₂[Ir(NH₃)Cl₅] with PhI(OAc)₂ in CH₂Cl₂ affords the Ir^V amido complex (PPh₄)[Ir(NH₂)Cl₅].     

Darstellung,Eigenschaften und Kristallstruktur von Na3[Yb(NH2)6]

Preparation, properties, and crystal structure of Na₃[Yb(NH₂)₆] Na₃[Yb(NH₂)₆] was prepared by the reaction of Na and Yb in the atomic ration 3:1 with ammonia at 150°C and 200 atm as a light grey microcrystalline powder. Colourless single crystals were obtained at 180°C and ～6000 atm. It decomposes rapidly at temperature above 140°C. At 250°C NaNH₂ nd a nitride phase results which crystallizes in the Nacl lattice type with a = 4.86 Å. Na₃[Yb(NH₂)₆] crystallizes orthorhombically with the lattice spacings a = 6.492 Å, b = 12.24 Å, and c = 21.33 Å with 8 formula units per unit cell. The space group is D–Pbca (No.61). The amide ions have a distorted close-packed arrangement with the layer sequence ABAC in the direction [010]. Ytterbium occupies on sixth, sodium one half of the octahedral interstices.     

Rubidiumhexaamidolanthanat und -neodymat,Rb3[La(NH2)6] und Rb3[Nd(NH2)6]; Strukturverwandtschaft zu K3[Cr(OH6)] und K4CdCl6

Rubidium Hexaamidolanthanate and -neodymate, Rb₃[La(NH₂)₆] and Rb₃[Nd(NH₂)₆]; Compounds. Structurally Related to K₃[Cr(OH)₆] and K₄CdCl₆ Colourless Rb₃[La(NH₂)₆] (a = 12.298(4) Å, c = 13.759(2) Å, N = 6, R3 c) and pale blue Rb₃[Nd(NH₂)₆] (a = 12.199(6) Å, c = 13.626(4) Å, N = 6, R32) have been prepared by the reaction of the corresponding metals (Rb: La resp. Nd = 3:1) with NH₃(P(NH₃) = 4–4.5 kbar) at 300°C. Single crystal x-ray methods gave their structures. It is shown by space group relations that these compounds are structurally related to one another and to further ternary amides as well as to K₃[Cr(OH)₆] and K₄CdCl₆.     

Die Einwirkung von Ammoniumfluorid auf Scandium: Synthese und Kristallstrukturen von (NH4)3[ScF6] und [Cu(NH3)4]3[ScF6]2

Action of Ammonium Fluoride on Scandium: Synthesis and Crystal Structures of (NH₄)₃[ScF₆] and [Cu(NH₃)₄]₃[ScF₆]₂ The action of (NH₄)F on scandium in copper ampoules yields either (NH₄)₃[ScF₆] or ScF₃ and a small quantity of [Cu(NH₃)₄]₃[ScF₆]₂, respectively, depending upon the molar ratio of the educts (NH₄)F : Sc (6 : 1 and 4 : 1, respectively) and temperature. (NH₄)₃[ScF₆] crystallizes with the cryolite type of structure: monoclinic, P2₁/n, Z = 2; a = 650.0(2); b = 651.4(2); c = 949.0(2) pm; β = 90.40(2)°, [Cu(NH₃)₄]₃[ScF₆]₂ is triclinic, P‐1, Z = 1; a = 821.1(2); b = 821.2(2); c = 822.7(2) pm; α = 90.04(3); β = 90.00(3); γ = 90.16(3)°. In its chemical behaviour against (NH₄)F, scandium parallels aluminium rather than gallium.     

Arsenidostannate mit Arsen-analogen [SnAs]-Schichten: Darstellung und Struktur von Na[Sn2As2], Na0,3Ca0,7[Sn2As2], Na0,6Sr0,6[Sn2As2], Na0,6Ba0,4[Sn2As2] und K0,3Sr0,7[Sn2As2]

Arsenidostannates with [SnAs] Nets Isostructural to Grey Arsenic: Synthesis and Crystal Structure of Na[Sn₂As₂], Na_0.3Ca_0.7[Sn₂As₂], Na_0.4Sr_0.6[Sn₂As₂], Na_0.6Ba_0.4[Sn₂As₂], and K_0.3Sr_0.7[Sn₂As₂] The metallic lustrous compounds Na[Sn₂As₂], Na_0.3Ca_0.7[Sn₂As₂], Na_0.4Sr_0.6[Sn₂As₂], Na_0.6Ba_0.4[Sn₂As₂] and K_0.3Sr_0.7[Sn₂As₂] were prepared from melts of mixtures of the elements. The compounds crystallize in the trigonal system (space group R3 m, No. 166, Z = 3) with lattice constants see in “Inhaltsübersicht”. The structures are isotypic to Sr[Sn₂As₂] containing puckered [SnAs] nets which are stacked with a sequence of six layers. The E(I)/E(II) atoms are located between each second [SnAs] layer in trigonal antiprismatic interstices formed by As atoms. In the resulting [Sn₂As₂] double layers the _∞²[SnAs] nets are stacked in such a way that additional Sn—Sn contacts arise.     

Synthese und Strukturaufklärung von neuen (Eisencarbonyl)zinkund ‐cadmiumchlorid‐Derivaten

Syntheses and Structure Elucidations of Novel (Ironcarbonyl)zinc and ‐cadmium Chloride Derivatives Reactions of zinc/cadmium chloride with Na₂[Fe(CO)₄] lead to a number of new (iron carbonyl)zinc/cadmium chlorides, wherein the reaction course depends on the used solvent used. In the reaction of ZnCl₂ with Na₂[Fe(CO)₄], three new substances can be prepared. The compound [Zn₂Cl₂Fe(CO)₄(THF)₂] ( 1 ), which consists of neutral polymeres, is formed in THF, the ionic compound [Na(DME)₃][Zn₂Cl₃Fe(CO)₄] ( 2 ) forms in DME, and from a mixture of THF and TMEDA the compound [Zn₂Cl₂Fe(CO)₄(TMEDA)₂] ( 3 ) is obtained as a monomere. Also by using CdCl₂, the reaction with Na₂[Fe(CO)₄] in THF leads to the polymeric compound ([(Cd₄Cl₆)Fe(CO)₄(THF)₅] ( 4 )). Carrying out the reaction in a mixture of toluene and DME leads to the formation of the ionic compound [Na(DME)₃]₂[Cd₆{Fe(CO)₄}₆Cl₂(DME)₂] ( 5 ) in which an annular dianion consisting of twelve metal atoms is found. From an aqueous solution and subsequent work‐up in THF, the compound [Fe(THF)₄(H₂O)₂][Cd₈{Fe(CO)₄}₄Cl₉(THF)₆]₂ ( 6 ) can be prepared which contains an cluster anion that is built of anellated six membered rings.     

The Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 3. Unsymmetrical 3:1, 1:3, 3:2, 4:1, 1:4, 4:2, 2:4, 1:5 1:6 and 6:1 Type Electrolytes. Dilute Aqueous Solutions of Rare Earth Salts, Various Cyanides and other Salts

Electrical conductivities of dilute aqueous solutions for unsymmetrical electrolytes of the type 3:1, 1:3, 3:2, 4:1, 1:4, 4:2, 2:4, 1:5 1:6 and 6:1 are reexamined in the framework of the Quint-Viallard conductivity equations, in order to obtain a uniform representation of their conductivities. The molar and equivalent limiting conductances were evaluated with ion association constants, which were treated as adjustable parameters. The derived values were compared with corresponding results from the literature. The following electrolytes are considered: rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er) halides, perchlorides, nitrates and sulfates; hexamminecobalt and tris-ethylenediaminecobalt halides, perchlorides, nitrates and sulfates; [Ni₂(trien)₃]Cl₄, [Pt(pn)₃]Cl₄, [Co₂(trien)₃]Cl₆; cyanides K₃[Fe(CN)₆], K₃[Co(CN)₆], M₃[W(CN)₈] with M=Na, K, Rb, Cs; Ca₂[Fe(CN)₆], K₄[Fe(CN)₆], K₄[Mo(CN)₈], K₄[W(CN)₈], K₄[Ru(CN)₈], (Me₄N)₄[Fe(CN)₆], (Pr₄N)₄[Fe(CN)₆], K₄[Mo(CN)₈], (Me₄N)₄[Mo(CN)₈], (Et₄N)₄[Mo(CN)₈] and (Pr₄N)₄[Mo(CN)₈]; phosphates Na₄P₂O₇, Na₄P₄O₁₂, Na₅P₃O₁₀, Na₆P₆O₁₈ and (Me₄N)₄P₄O₁₂.     

Complex Carbonates of Iron(III)

The complex carbonates of iron(III) are shown to be anionic in nature. The solutions containing these complexes show a maximum absorbance at 460 nm. The complex carbonates of iron(III), viz., (i) K₆[Fe₂(OH)₂(CO₃)₅] · H₂O, — (ii) Na₂[Fe₃O₂(OH)₃(CO₃)₂], — (iii) K[Co(NH₃)₆]₂[Fe₃(OH)₄(CO₃)₆], — (iv) K₅[Co(NH₃)₆]₃[Fe₃(OH) ₄(CO₃)₆]₂, — (v) K[Co(NH₃)₆][Fe₂(OH)₄(CO₃)₃], and (vi) NH₄[Co(NH₃)₆][Fe₂(OH)₄(CO₃)₃] are isolated and studied by thermogravimetry. The infrared spectra of these compounds are recorded and probable band assignments made. Besides, the reaction between KHCO₃ and Fe(NO₃)₃ was studied through chemical and physicochemical methods.     

Umsetzung des Silberamidoselenates mit Ammoniak und Darstellung von Imidodiselenaten

Zusammenfassung Im Unterschied zu AgSO₃NH₂, das sich in flüssigem NH₃ glatt auflöst und quantitativ in den Aminkomplex [Ag(NH₃)₂] SO₃NH₂ übergeht, reagiert AgSeO₃NH₂ stark exotherm, wobei neben [Ag(NH₃)₂]SeO₃NH₂, NH₄SeO₃NH₂ und sehr kleinen Mengen einer bisher nicht identifizierten Substanz durch Kondensation, die etwa zu 60% verläuft, auch das Trisilbersalz der Imidodiselensäure als Aminkomplex [Ag(NH₃)₂]₃[O₃Se–N–SeO₃] entsteht.Nach einem einfachen Reinigungsverfahren wurde aus diesem Komplex Ag₃[O₃Se–N–SeO₃] erhalten und daraus die Imidodiselenate Na₃[O₃Se–N–SeO₃] · 3 H₂O, K₃[O₃Se–N–SeO₃] · H₂O, (NH₄)₃[O₃Se–N–SeO₃] und Ba₃[O₃Se–N–SeO₃]₂ · 5H₂O als kristalline Substanzen dargestellt, die näher charakterisiert und thermogravimetrisch und differentialthermoanalytisch untersucht wurden.

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Reaction of silver amidoselenate with ammonia and preparation of imidodiselenates

Contrary to AgSO₃NH₂, which dissolves in liquid NH₃ with quantitat. conversion to [Ag(NH₃)₂]SO₃NH₂, AgSeO₃NH₂ in a strongly exothermic reaction yields several products: [Ag(NH₃)₂]SeO₃NH₂, NH₄SeO₃NH₂, small amounts of an as yet unidentified compound, and in a condensation reaction to about 60% the amine complex of the trisilver salt of imido-diselenic acid.A simple purification gives Ag₃[O₃Se–N–SeO₃], and from this the crystalline imido-diselenates Na₃[O₃Se–N–SeO₃] · 3 H₂O, K₃[O₃Se–N–SeO₃] · H₂O, (NH₄)₃[O₃Se–N–SeO₃] and Ba₃[O₃Se–N–SeO₃]₂ · 5 H₂O where prepared and characterized thermogravimetrically, and by the method of differential thermoanalysis.

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Mit 3 Abbildungen

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K. Dostál undA. Rika, Z. Chem.8, 153 (1968). (Vorläufige kurze Mitteilung).     

Synthesis of nanosize Co-Rh systems and study of their properties

Precursor compounds [Co(NH₃)₆][Rh(NO₂)₆] and [Co(NH₃)₆][Co(NO₂)₆], solid solutions [Co(NH₃)₆] [Rh(NO₂)₆]_1−x [Co(NO₂)₆] _x , and solid solutions Na₃[Rh_1−x Co _x (NO₂)₆] were synthesized and studied by IR spectroscopy and elemental, X-ray phase, X-ray diffraction, and thermogravimetric analyses. X-ray phase analysis was employed to examine products of thermal decomposition of precursors in the atmospheres of hydrogen and helium. Catalysts with a Co-Rh active system, supported by ZrO₂, were prepared and tested in the reaction of steam conversion of ethanol.     

Darstellung,Ramanspektren und Kristallstrukturen von V2O3(SO4)2, K[VO(SO4)2] und NH4[VO(SO4)2]

Preparation, Raman Spectra, and Crystal Structures of V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] The oxo-sulfato-vanadates(V) V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] have been prepared as crystals suitable for X-ray structure determination. In all structures sulfate acts as an unidentate ligand only toward a single vanadium atom. The structure of V₂O₃(SO₄)₂ consists of a threedimensional network of pairs of cornershared VO₆ octahedra with one terminal oxygen atom each, and SO₄ tetrahedra. All oxygen atoms of the sulfate ions are coordinated. NH₄[VO(SO₄)₂] and K[VO(SO₄)₂] are isostructural. VO₆ octahedra with one terminal oxygen atom and pairs of sulfate tetrahedra form infinite chains by corner sharing. The chains are weakly interlinked to layers. The sulfate ions are distorted towards planar SO₃ molecules and single oxygen atoms attached to vanadium. This structural detail gives an explanation for the mechanism of the reversible reaction K[VO(SO₄)₂] ? K[VO₂(SO₄)] + SO₃ at 400°C. Raman spectra of the compounds have been recorded and interpreted with respect to their structures. Crystal data: V₂O₃(SO₄)₂, monoclinic, space group P2₁/a, a = 947.2(4), b = 891.3(3), c? 989.1(4) pm, β = 104.56(3)°, Z = 4, 878 unique data, R(R_w) = 0.039(0,033); K[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(2), b = 869.6(9), c = 1 627(1)pm, Z = 4, 642 unique data, R(R_w) = 0,11(0,10); NH₄[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(1), b = 870.0(2), c = 1 676.7(4)pm, Z = 4, 768 unique data, R(R_w) = 0.088(0.083).     

Strukturchemische Untersuchungen von Monammin-Kupfer(I)-Komplexen: [CuNH3]2[Pt(CN)6], [CuNH3]2[Pt(CN)4] und Cu3[Co(CN)6]-2 NH3

Structurally Chemical Investigation of Monoammin Copper (I) Complexes : [CuNH₃]₂[Pt(CN)₆], [CuNH₃]₂[Pt(CN)₄] and Cu₃[Co(CN)₆] · 2NH₃ The preparation and the properties of [CuNH₃]₂[Pt(CN)₆], [CuNH₃]₂[Pt(CN)₄] and Cu₃[Co(CN)₆] · 2NH₃ are described. I.R. and Raman spectra have been recorded and assigned. According to X-ray powder diagrams, [CuNH₃]₂[Pt(CN)₆] crystallizes in the trigonal space group D–P3 ml, a = 7.771, c = 5.988 Å, Z = 1. According to the spectroscopic and crystallographic data, it is concluded that the Cu_I ion is coordinated with one NH₃ group and with the N atoms of the cyanometallate anions. The coordination number of the Cu⁺ is 4 in [CuNH₃]₂[Pt(CN)₆] and 3 in [CuNH₃]₂[Pt(CN)₄]. In the Cu₃[Co(CN)₆] · 2 NH₃ complex two Cu atoms have the coordination number 2, the third Cu atom 4.     

Synthese und Kristallstrukturen von NH4[Si(NH3)F5] und [Si(NH3)2F4]

Synthesis and Crystal Structures of NH₄[Si(NH₃)F₅] and [Si(NH₃)₂F₄] Single crystals of NH₄[Si(NH₃)F₅] and [Si(NH₃)₂F₄] are obtained by reaction of silicon powder with NH₄HF₂ in sealed Monel ampoules at 400°C. NH₄[Si(NH₃)F₅] crystallizes with the tetragonal space group P4/n (no. 85) with a = 614.91(7) pm, c = 721.01(8) pm, Z = 2. Characteristic for the structure is the anionic octahedron [Si(NH₃)F₅]^?. Si(NH₃)₂F₄ crystallizes with the monoclinic space group P2₁/c (no. 14) with a = 506.9(1) pm, b = 728.0(1) pm, c = 675.9(1), β = 93,21(2)°, Z = 2. Trans-[Si(NH₃)₂F₄] molecules are characteristic for this structure.     

Die Kristallstrukturen der Hexachlorometallate NH4[SbCl6], NH4[WCl6], [K(18‐Krone‐6)(CH2Cl2)]2[WCl6]·6CH2Cl2 und (PPh4)2[WCl6]·4CH3CN

Crystal Structures of the Hexachlorometalates NH₄[SbCl₆], NH₄[WCl₆], [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ and (PPh₄)₂[WCl₆]·4CH₃CN The crystal structures of the title compounds were determined by single crystal X‐ray methods. NH₄[SbCl₆] and NH₄[WCl₆] crystallize isotypically in the space group C2/c with four formula units per unit cell. The NH₄⁺ ions occupy a twofold crystallographic axis, whereas the metal atoms of the [MCl₆]^— ions occupy a centre of inversion. There exist weak interionic hydrogen bridges. [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ crystallizes in the orthorhombic space group R3¯/m with Z = 3. The compound forms centrosymmetric ion triples, in which the potassium ions are coordinated with a WCl₃ face each. In trans‐position to it the chlorine atom of a CH₂Cl₂ molecule is coordinated so that, together with the oxygen atoms of the crown ether, coordination number 10 is achieved. (PPh₄)₂[WCl₆]·4CH₃CN crystallizes in the monoclinic space group P2₁/c with Z = 4. This compound, too, forms centrosymmetric ion triples, in which in addition the acetonitrile molecules are connected with the [WCl₆]^2— ion via weak C—H···Cl contacts.     

Darstellung und Kristallstruktur von (NH4)2[V(NH3)Cl5]. Die Kristallchemie der Salze (NH4)2[V(NH3)Cl5], [Rh(NH3)5Cl]Cl2 und M2VXCl5 mit M = K,NH4, Rb,Cs und X = Cl,O

Preparation and Crystal Structure of (NH₄)₂[V(NH₃)Cl₅]. The Crystal Chemistry of the Compounds (NH₄)₂[V(NH₃)Cl₅], [Rh(NH₃)₅Cl]Cl₂, and M₂VXCl₅ with M = K, NH₄, Rb, Cs and X ? Cl, O (NH₄)₂[V(NH₃)Cl₅] crystallizes like [Rh(NH₃)₅Cl]Cl₂ in the orthorhombic space group Pnma with Z = 4. The compounds are built up by isolated NH₄⁺ or Cl^? and complex MX₅Y ions. The following distances have been observed: V? N: 213.8, V? Cl: 235.8–239.1, Rh? N: 207.1–208.5, Rh? Cl: 235.5 pm. Both structures differ from the K₂PtCl₆ type mainly in the ordering of the MX₅Y polyhedra. The compounds M₂VCl₆ and M₂VOCl₅ with M = K, NH₄, Rb, and Cs crystallize with exception of the orthorhombic K₂VOCl₅ in the K₂PtCl₆ type. The ordering of the MX₅Y polyhedra in the compounds (NH₄)₂[V(NH₃)Cl₅], [Rh(NH₃)₅Cl]Cl₂ and K₂VOCl₅ enables a closer packing.     

Reaktionen am metallischen Substrat: Einkristalle von Ni(NH3)2V2F8

Reactions at the Metallic Substrate: Single Crystals of Ni(NH₃)₂V₂F₈ Except for the main product (NH₄)₂[TaF₇] and some [Ni(NH₃)₆][TaF₆]₂, the new light green Ni(NH₃)₂V₂F₈ is obtained by the reaction of (NH₄)F with tantalum and vanadium (molar ratio of (NH₄)F : Ta : V = 36 : 6 : 1) at 400 °C in a sealed Monel ampoule (Cu32Ni68). The crystal structure (orthorhombic, Fmmm, Z = 4, a = 752.9(1), b = 762.9(1), c = 1307.6(2) pm) is related to that of (NH₄)[VF₄]. According to {Ni(NH₃)₂}_0,5[VF₄], corrugated layers of vertex-connected octahedra [VF_4/2F_2/1] are stacked in the [001] direction. Between these layers trans-{Ni(NH₃)₂} units are inserted so that Ni²⁺ enhances its coordination number to 6 by two times two F^– from the layers above and below.     

Thio- und Selenomercurate(II). K6[HgS4], K6[HgSe4], Rb6[HgS4] und Rb6[HgSe4]

Thio- and Selenomercurates(II). K₆[HgS₄], K₆[HgSe₄], Rb₆[HgS₄] and Rb₆[HgSe₄] We prepared by annealing intimate mixture of pure samples of K₂S, K₂Se, Rb₂S, and Rb₂Se with HgS or HgSe [360–380°C, 7d, Duran-glass-seal with Argon] with hexagonal Na₆ZnO₄ isotypic new mercurates: K₆[HgS₄] [bright citronic yellow a = 9.98₅, c = 7.65₂ Å], K₆[HgSe₄] [light orange yellow a = 10.3₆, c = 7.88₃ Å], Rb₆[HgS₄] [bright yellow a = 10.3₄, c = 7.94₂ Å], Rb₆[HgSe₄] [orange-red a = 10.7₂, c = 8.19₂ Å]. The crystal structure of K₆ Hgs₄ is elucidated by using diffractometer data of single crystals: P63mc, C⁴_6v, it is R = 6.6% for 304 reflexes [h k o–h k 4, anisotropic refinement MoKα]; for position and parameters see text d_rö = 2.83₅, d_pyk = 2.99 g · cm^?3. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, are calculated and discussed.     

Synthese und Kristallstruktur von [Na(12-Krone-4)2]2[Hg(Se4)2] · 1,5 DMF

Synthesis and Crystal Structure of [Na(12-Crown-4)₂]₂[Hg(Se₄)₂] · 1.5 DMF . The title compound has been prepared by the reaction of Na₂Se₄ with mercury acetate in DMF solution in the presence of 15-crown-5, forming dark red crystal needles. [Na(12-crown-4)₂]₂[Hg(Se₄)₂] · 1.5 DMF crystallizes in the space group C2/c with eight formula units per unit cell. The structure was determined with 3 824 observed unique reflections, R = 0.085. Lattice dimensions at - 70°C: a = 2 884(2), b = 1 407.7(7), c = 2 843(2) pm, β = 93.93(5)°. The structure consists of [Na(12-crown-4)₂]⁺ ions with a sandwichlike coordination of the crown ether molecules, and of [Hg(Se₄)₂]^2? ions, in which the mercury atom is coordinated by two tetraselenido ions in a chelating fashion. The [Hg(Se₄)₂]^2? ions are arranged to infinite chains via Se…?Se contacts.     

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.