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.     

Strukturen aus AlB2- und CeMg2Si2-analogen Einheiten. Die Verbindungen Eu3Pd4As4, Ca4Pd5P5 und Ca5Pd6P6

Structures with AlB₂- and CeMg₂Si₂-Type Units. The Compounds Eu₃Pd₄As₄, Ca₄Pd₅P₅, and Ca₅Pd₆P₆ The new compounds Eu₃Pd₄As₄, Ca₄Pd₅P₅, and Ca₅Pd₆P₆ (space groups and lattice constants see ?Inhaltsübersicht”?) have been prepared by heating mixtures of the elements. Their structures were determined by means of single-crystal X-ray methods and contain exclusively units, which are characteristic for the AlB₂- and CeMg₂Si₂-type. The non-metal atoms are isolated from each other or connected to pairs; the ratio between these two kinds can be interpreted by ionic splittings of the formulas.     

Darstellung,thermisches Verhalten und Kristallstruktur des Calciumarsenidchlorids Ca3AsCl3

Preparation, Thermal Stability, and Crystal Structure of the Calcium Arsenide Chloride Ca₃AsCl₃ CaAsCa₃AsCl₃ was prepared as a grayish white, microcrystalline powder by the reaction of Ca, As, and CaCl₂ in the molar ratio 3:2:3 and by the reaction of “Ca₃As₂” and CaCl₂ in the molar ratio 1:3. Colourless single crystals of the compound were obtained. Ca₃AsCl₃ begins to decompose reversibly at 1 025°C by forming the phase Ca_{2? x}As_{1? x}Cl_1+x with x = 0.1₃ and CaCl₂. Single crystal investigations show that Ca₃AsCl₃ is isotypic with Mg₃NF₃; see: “Inhaltsübersicht”.     

Neuartige Polyanionen in Zintlphasen. Zur Kenntnis von Ca3Si2As4, Ca3Ge2As4, Sr3Si2As4 und Sr3Ge2As4

New Polyanions in Zintl Phases. On Ca₃Si₂As₄, Ca₃Ge₂As₄, Sr₃Si₂As₄, and Sr₃Ge₂As₄ The new compounds Ca₃Si₂As₄, Ca₃Ge₂As₄, Sr₃Si₂As₄ and Sr₃Ge₂As₄ crystallize in the monoclinic system with lattice constants see “Inhaltsübersicht”. There are two new structure types. Both contain Si₂As₆ or Ge₂As₆ groups connected to chains in different ways. These chains are ordered parallel to each other to sheets with the alkaline-earth atoms between them.     

Sm2As4O9: Ein ungewöhnliches Samarium(III)‐Oxoarsenat(III) gemäß Sm4[As2O5]2[As4O8]

Sm₂As₄O₉: An Unusual Samarium(III) Oxoarsenate(III) According to Sm₄[As₂O₅]₂[As₄O₈] Pale yellow single crystals of the new samarium(III) oxoarsenate(III) with the composition Sm₄As₈O₁₈ were obtained by a typical solid‐state reaction between Sm₂O₃ and As₂O₃ using CsCl and SmCl₃ as fluxing agents. The compound crystallizes in the triclinic crystal system with the space group (No. 2, Z = 2; a = 681.12(5), b = 757.59(6), c = 953.97(8) pm, α = 96.623(7), β = 103.751(7), γ = 104.400(7)°). The crystal structure of samarium(III) oxoarsenate(III) with the formula type Sm₄[As₂O₅]₂[As₄O₈] (≡ 2 × Sm₂As₄O₉) contains two crystallographically different Sm³⁺ cations, where (Sm1)³⁺ is coordinated by eight, but (Sm2)³⁺ by nine oxygen atoms. Two different discrete oxoarsenate(III) anions are present in the crystal structure, namely [As₂O₅]^4? and [As₄O₈]^4?. The [As₂O₅]^4? anion is built up of two Ψ¹‐tetrahedra [AsO₃]^3? with a common corner, whereas the [As₄O₈]^4? anion consists of four Ψ¹‐tetrahedra with ring‐shaped vertex‐connected [AsO₃]^3? pyramids. Thus at all four crystallographically different As³⁺ cations stereochemically active non‐binding electron pairs (“lone pairs”) are observed. These “lone pairs” direct towards the center of empty channels running parallel to [010] in the overall structure, where these “empty channels” being formed by the linkage of layers with the ecliptically conformed [As₂O₅]^4? anions and the stair‐like shaped [As₄O₈]^4? rings via common oxygen atoms (O1 – O6, O8 and O9). The oxygen‐atom type O7, however, belongs only to the cyclo‐[As₄O₈]^4? unit as one of the two different corner‐sharing oxygen atoms.     

Synthesis and Onwards Coordination of an AsI Centered Zwitterion

The bis(phosphino)borate ligand class is used as an anionic anchor to stabilize reactive, low coordinate arsenic centers. The neutral, zwitterionic As^I species, 2 , is formed very cleanly, and isolated in good yields using cyclohexene as a halogen scavenger. The uniqueness of this heterocyclic As^I compound is on display with the coordination to Group 6 metal centers, ( 2 M(CO)₅ ; M=Cr, Mo, W). The arsenic? metal bond lengths are longer than the related AsPh₃ complexes suggesting that compound 2 is a weak sigma donor. The metal complexes reveal a trigonal pyramidal arsenic atom, which provides the first experimental evidence for the presence of two “lone pairs” of electrons on the As^I center. When more flexible and more electron‐donating isopropyl substituents were used, an intermediate (compound 5 ) in the formation of low coordinate pnictogen compounds was crystallographically characterized. This structure, formally a base‐stabilized dichloroarsenium cation, provides an alternative mechanistic proposal to the one described in the literature.     

Darstellung,Struktur und Temperaturabhängigkeit der Phasenbreite der Phase Ca2−xAs1−xBr1+x und thermisches Verhalten der Verbindung Ca3AsBr3

Preparation, Crystal Structure, and Temperature Dependence of the Homogeneity Range of the Phase Ca_2-xAs_1-xBr_1+x and Thermal Behaviour of Ca₃AsBr₃ The phase (Ca_2-x□_x)(As_1-xBr_1+x) (yellow, NaCl type lattice, x ? degree of substitution) was prepared from “Ca₃As₂” and CaBr₂ in different molar ratios in steel ampoules under argon at 900 and 950°C resp. The lattice constant as a function of the composition, the homogeneity range, and dependence of the bromine rich phase boundary on the temperature were determined. The structure was deduced from single crystal X-ray investigation and density measurements at different compositions. The thermal behaviour of Ca₃AsBr₃ (colourless, isotypic to Mg₃NF₃, prepared at 850°C) was studied by annealing samples in molybdenum ampoules under argon in the temperature range 900–1250°C and by differential thermal analysis. From the experimental results a section of the phase diagram Ca₃As₂?CaBr₂ was constructed.     

Phase equilibria in the Sn–As–Ge and Sn–As–P systems

T–x diagrams of polythermal GeAs–SnAs, GeAs–Sn₄As₃ sections of the Sn–As–Ge system and Sn₄P₃–Sn₄As₃ section of the Sn–As–P system were constructed using the results of X-ray powder diffraction and differential thermal analyses. It was found that the section GeAs–Sn₄As₃ is not quasi-binary due to realization of four-phase peritectic transformation L + SnAs ? GeAs + Sn₄As₃ at the temperature of 834 K. The quasi-binary section GeAs–SnAs represents a phase diagram of the eutectic type with the following coordinates of eutectic reaction: temperature of the eutectic point is 840 K, and composition is 20 mol% GeAs. In the Sn–As–P system, the existence of the solid-solution range indicated as (Sn₄As₃) _x (Sn₄P₃)_1?x  was defined. The polythermal section Sn₄P₃–Sn₄As₃ is not quasi-binary due to the fact that in the composition range with a high content of tin arsenide discussed section intersects the peritectic part of the three-phase volume (L + SnAs + α) of the ternary diagram.     

Polythermal section Sn4P3-Sn4As3

The T-x diagram of the polythermal section Sn₄P₃-Sn₄As₃ of the Sn-P-As system was constructed using the results of X-ray powder diffraction and differential thermal analyses. A continuous series of solid solutions (Sn₄P₃) _x (Sn₄As₃)_{1 ? x} was found to exist. The section is not quasi-binary; in a Sn₄As₃-rich region, this section intersects the peritectic part of the three-phase volume (L + SnAs + α) of the ternary diagram.     

Syntheses and Crystal Structures of Four New Ammoniates with Heptaarsenide (As$\rm{_{7}^{3-}}$) Anions

The syntheses and X‐ray single‐crystal low‐temperature structures of the four new ammoniates [Li(NH₃)₄]₃As₇?NH₃ ( 1 ), [Rb(18‐crown‐6)]₃As₇?8 NH₃ ( 2 ), Cs₃As₇?6 NH₃ ( 3 ), and (Ph₄P)₂CsAs₇?5 NH₃ ( 4 ) are reported. The compounds were obtained by either direct reduction of As with Li/Cs in liquid NH₃, solvation of Cs₄As₆/Rb₄As₆ in liquid NH₃, or by extraction of solid Cs₃As₇. While compound 1 contains isolated As polyanions, As? M contacts (M=Na?Cs) lead to neutral [Rb(18‐crown‐6)]₃As₇ units in 2 , a three‐dimensional, extended network in 3 , and one‐dimensional, infinite [CsAs₇]^2? chains in 4 , respectively.     

The Neat Ternary Solid K5−xCo1−xSn9 with Endohedral [Co@Sn9]5− Cluster Units: A Precursor for Soluble Intermetalloid [Co2@Sn17]5− Clusters

A new type of Zintl phase is presented that contains endohedrally filled clusters and that allows for the formation of intermetalloid clusters in solution by a one‐step synthesis. The intermetallic compound K_5?xCo_1?xSn₉ was obtained by the reaction of a preformed Co? Sn alloy with potassium and tin at high temperatures. The diamagnetic saltlike ternary phase contains discrete [Co@Sn₉]^5? clusters that are separated by K⁺ ions. The intermetallic compound K_5?xCo_1?xSn₉ readily and incongruently dissolves in ethylenediamine and in the presence of 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane (2.2.2‐crypt), thereby leading to the formation of crystalline [K([2.2.2]crypt)]₅[Co₂Sn₁₇]. The novel polyanion [Co₂Sn₁₇]^5? contains two Co‐filled Sn₉ clusters that share one vertex. Both compounds were characterized by single‐crystal X‐ray structure analysis. The diamagnetism of K_5?xCo_1?xSn₉ and the paramagnetism of [K([2.2.2]crypt)]₅[Co₂Sn₁₇] have been confirmed by superconducting quantum interference device (SQUID) and EPR measurements, respectively. Quantum chemical calculations reveal an endohedral Co^1? atom in an [Sn₉]^4? nido cluster for [Co@Sn₉]^5? and confirm the stability of the paramagnetic [Co₂Sn₁₇]^5? unit.     

Synthese und Kristallstruktur von Ti12Sn3O10 – einem niedervalenten Oxid des Titans mit oxidischem Gerüst und intermetallischen „Inseln”︁

Synthesis and Crystal Structure of Ti₁₂Sn₃O₁₀ – a Low Valent Oxide of Titanium with an Oxidic Network and Intermetallic ”︁Islands”︁”︁ The new ternary compound Ti₁₂Sn₃O₁₀ is obtained by the reaction of Ti, TiO₂ and Sn at 1500 °C. According to the single crystal structure analysis (cubic, space group Fm3m, a = 13.5652(9) Å, Z = 8, wR₂(I) = 0.048, R₁(F) = 0.020) the air stable compound represents a new structure type combining structural features of oxides and intermetallics. While tin is surrounded only by titanium the five different Ti atoms have oxidic and metallic coordination spheres as well, explaining the quite low averaged oxidation number. The crystal structure is characterized by a threedimensional net of Ti₄O‐tetrahedra and trigonal bipyramides Ti₅O. In the voids there are intermetallic ”︁islands”︁”︁ of a composition Ti₃₃Sn₆ with a diameter of about 10 Å.     

Elektronenmangelverbindungen des Galliums Zur Kenntnis von Ca3Ga5

Electron Deficient Compounds of Gallium: Crystal Structure of Ca₃Ga₅ The stoichiometry of the formerly described compound Ca₂Ga₃ is corrected to Ca₃Ga₅. This compound crystallizes in the orthorhombic system, space group Cmcm (No. 63) with the lattice constants see ?Inhaltsübersicht”?. In the structure there is a Ga framework for which on the basis of the Gillespie/Nyholm conception and by calculating the bond numbers according to Pauling a characteristic electron concentration can be derived.     

Darstellung und kristallographische Daten von Tetracalciumplatinoxid Ca4PtO6

On synthesising Ca-silicates from a CaCl₂-flux in the presence of Platinum, Ca₄PtO₆ was found. The compound crystallises orthorhombic (see ?Inhaltsübersicht”?). Relations to Sr₄PtO₆ are described.     

Ab initio study of the nature of the chemical bond and electronic structure of the layered phase Ca10(Pt4As8)(Fe2As2)5 as a parent system in the search for new superconducting iron-containing materials

Ab initio calculations were used in a detailed study of chemical bonding and electronic structure of the recently discovered superconducting tetragonal phase Ca₁₀(Pt₄As₈)(Fe₂As₂)₅ (T_C 25 K). The Ca₁₀(Pt₄As₈)(Fe₂As₂)₅ phase is metal-like, mainly due to the Fe3d states of the (Fe₂As₂)₅ blocks. The electronic spectrum of the (Pt₄As₈) blocks is similar to a semi-metal with very low density of states at the Fermi level. Chemical bonding in Ca₁₀(Pt₄As₈)(Fe₂As₂)₅ may be described as a mixture of anisotropic contributions of covalent, ionic, and metallic interatomic and inter-block interactions.     

Mischkristallbildung in den Systemen As2O5/SbAsO5 und As2O5/AsPO5 Bestimmung der spontanen Deformationen und Verfeinerung der Kristallstrukturen der ternären Randphasen

Formation of Solid Solutions within the Systems As₂O₅/SbAsO₅ and As₂O₅/AsPO₅ Determinations of the Spontaneous Deformations and Refinements of the Crystal Structures of the Ternary Border Phases As₂O₅ allows for substitution of tetrahedrally and octahedrally coordinated arsenic by phosphours and antimony, respectively. The solid solutions As_{2? x}P_xO₅ and Sb_xAs_{2? x}O₅ range from x = 0.5 to 1.0 and x = 0.75 to 1.0. The crystal structures of the ternary oxides AsPO₅ and SbAsO₅ have been refined by profile fitting of x-ray powder diagrams; both are isostructural to As₂O₅, for lattice constants see ?Inhaltsübersicht”?. Both are undergoing ferroelastic/paraelastic phase transitions which are completed at 600°C (AsPO₅) and 760°C (SbAsO₅), the spontaneous strains at room temperature being ?_s = 1.50 × 10^?2 and 2.27 × 10^?2 respectively.     

Ba3Sn2P4, ein neues Inophosphidostannat(III)

Ba₃Sn₂P₄, a New Inophosphidostannate(III) The new compound Ba₃Sn₂P₄ crystallizes in the monoclinic system, space group P2₁ (No. 4) with the lattice constants see “Inhaltsübersicht”. Distorted Sn₂P₆ octahedra are connected by common edges to infinite chains.     

Cyclische Diazastannylene. XXVIII. Anorganische Polycyclen aus der Reaktion eines Bis(amino)-stannylens bzw. eines Iminostannylens mit SnCl2, SnBr2 und tert-Butoxizinn(II)-chlorid bzw. -bromid

Cyclic Diazastannylenes. XXVIII. Inorganic Polycyclic Compounds from the Reaction of Bis(amino)stannylene or Iminostannylene with SnCl₂, SnBr₂, and tert-Butoxitin(II) Chloride or Bromide The cyclic bis(amino)stannylene 1 may react with tert-butoxitin(II) chloride or bromide yielding a Lewis acid-base adduct 4 resp. 5 , in which the two molecules are held together via N→Sn (233.8(3) pm) and O→Sn (215.1(2) pm) bonds. The resulting adduct 4 contains therefore two four membered rings sharing one common edge as found by X-ray structure determination. If 1 is allowed to react with SnCl₂ or SnBr₂, the salts Me₂Si(N^tBu)₂Sn₂Br⁺Sn₂Br₅^? ( 7 ) are formed. Structure analysis reveals the cations in 6 and 7 to be very similar: SnCl⁺ and SnBr⁺ are coordinated by the “trihapto ligand” 1 in a way resulting a polycyclic SiN₂Sn₂X-arrangement. To a central Sn₂N₂ tetrahedron Si and halogen X are added occupying and bridging two opposite edges (mean values: N? Sn = 232(5) ( 6 ), N? Sn = 230(2) ( 7 ), Sn? C1 = 265(1), Sn? Br = 275(1) pm). The reaction intermediate (SnN^tBu)₂ adds to SnCl₂ to form the crystalline polymer ( ^tBuN)₂Sn₃C1₂ (8) . X-ray structure determination reveals the solid to be built up by one-dimensional chains of polycyclic Sn₃(N^tBu)₂C1₃ sharing two chlorine atoms with neighbouring units. The unit Sn₃(N^tBu)₂C1₃ can be visualized as an equilateral triangle of chlorine atoms, on which a smaller triangle of tin atoms is superimposed; the corners of the smaller triangle being located in the middle of the larger triangle's edges. The tin atoms are bipyramidally coordinated by two N? ^tBu-groups thus forming a nearly perfect Sn₃N_2s trigonal bipyramide (Sn? N = 222.7(3) pm). Two chlorine atoms of the triangle are connected to neighbouring units, the chlorine atoms thus attain an unusual nearly square-planar coordination sphere (Sn? Cl(mean) = 308(5) pm). The tertbutyl groups at the nitrogen atoms “screen” the inorganic part of the structure leading to a layer structure.     

Iodination of cyclo‐E5‐Complexes (E=P,As)

In a high‐yield one‐pot synthesis, the reactions of [Cp*M(η⁵‐P₅)] (M=Fe ( 1 ), Ru ( 2 )) with I₂ resulted in the selective formation of [Cp*MP₆I₆]⁺ salts ( 3 , 4 ). The products comprise unprecedented all‐cis tripodal triphosphino‐cyclotriphosphine ligands. The iodination of [Cp*Fe(η⁵‐As₅)] ( 6 ) gave, in addition to [Fe(CH₃CN)₆]²⁺ salts of the rare [As₆I₈]^2? (in 7 ) and [As₄I₁₄]^2? (in 8 ) anions, the first di‐cationic Fe‐As triple decker complex [(Cp*Fe)₂(μ,η^5:5‐As₅)][As₆I₈] ( 9 ). In contrast, the iodination of [Cp*Ru(η⁵‐As₅)] ( 10 ) did not result in the full cleavage of the M?As bonds. Instead, a number of dinuclear complexes were obtained: [(Cp*Ru)₂(μ,η^5:5‐As₅)][As₆I₈]_0.5 ( 11 ) represents the first Ru‐As₅ triple decker complex, thus completing the series of monocationic complexes [(Cp^RM)₂(μ,η^5:5‐E₅)]⁺ (M=Fe, Ru; E=P, As). [(Cp*Ru)₂As₈I₆] ( 12 ) crystallizes as a racemic mixture of both enantiomers, while [(Cp*Ru)₂As₄I₄] ( 13 ) crystallizes as a symmetric and an asymmetric isomer and features a unique tetramer of {AsI} arsinidene units as a middle deck.