Die Gasphasenintercalation von Graphit durch SbCl4F

Gas Phase Intercalation of Graphite by SbCl₄F Gas Phase Intercalation of Graphite by SbCl₄F using a two-zone technique is a method to prepare intercalation compounds of different stage index n in temperature range between 120 and 140°C. The reaction is a process of successive decrease of stage index. Increasing the reaction time, i. e. concentration, regions of pure stages alternate with two-phase regions. Intercalation compounds were characterized by X-ray technique, EPMA, and chemical methods. The compounds are stable in ordinary air, with aqueous HCl as well as KOH only pentavalent but not any trivalent antimony can be removed. The identity periods along c-axis in pure stages are I_c = 9.33 Å (n = 1), 12.72 Å (n = 2), 16.06 Å (n = 3) and 19.40 Å (n = 4). A (√7 × √ 7) 19.1° in-plane structure of intercalants was found. The uptake curve of mass with time reveals a discontinuity connected with formation of stage 2. Concave shape of curve during starting period at 120 and 125°C will be interpreted as a consequence of an induction time. From X-ray and EPMA studies it may be concluded that nucleation at the prismatic crystal edges controls the kinetics of reaction. Assuming a first order kinetics of filling the vacant sites, the same activation energy in case of formation of stage 1 and stage 2 have been determined approximately (97 and 102 kJ/mol).     

Untersuchungen an Polyhalogeniden III. Tetrammin-kupfer(II)-tetraiodid, [Cu(NH3)4I2 · I2], und Tetrammin-kupfer(II)-hexaiodid, [Cu(NH3)4I3]I3

Studies on Polyhalides. III. Crystal Structures of [Cu(NH₃)₄I₂ · I₂] and [Cu(NH₃)₄I₃]I₃ Tetramminecopper(II)tetraiodide [Cu(NH₃)₄I₂ · I₂] (I) crystallizes monoclinically in the space group C2/m with a = 1 185.9 pm, b = 892.8 pm, c = 656.8 pm, β = 111.10° and Z = 2 formula units. Tetramminecopper(II)hexaiodide [Cu(NH₃)₄I₃]I₃ (II) crystallizes orthorhombically in the space group Pnnm with a = 874.9 pm, b = 1 089.8 pm, c = 885.3 pm, and Z = 2 formula units. A special feature of these structures are coordinated polyiodide ions I₄^2? (I) or I₃^? (II). In both compounds four coplanar nitrogen atoms and two axial iodine atoms form a quasi-octahedral coordination around copper with the usual (4+2)-tetragonal distortion. The copper ions are connected by linear, centrosymmetric polyiodide ions I₄^2? (I) or I₃^? (II). Therefore infinite planar zigzag chains of units [Cu(NH₃)₄I₄] (I) or [Cu(NH₃)₄I₃]⁺(II) are resulting. The counterion I₃^? (II) is intercalated between these chains.     

Isothiocyanat-Komplexe von Kupfer (II) mit quadratisch-planarer und tetragonal-pyramidaler Koordination: Struktur,Phasenumwandlungen und Redoxverhalten

Isothiocyanate Complexes of Copper(II) with Square-Planar and Tetragonal-Pyramidal Coordination: Structure, Phase Transitions, and Redox-Properties In dependence on the kind and size of the counter-cations Cu²⁺-ions form isothiocyanate complexes with different coordination number and geometry. The structures of compounds with square-planar coordination [(NEt₄)₂[Cu(NCS)₄] · CHCl₃ (brown): Space group 14/mmm, Z = 2; a = 1204.3(2) pm, c = 1154.2(3) pm] and with tetragonal-pyramidal polyhedra [(NEt₄)₃[Cu(NCS)₅] · SM (green, SM: unidentified solvent molecule): Space group P2₁/c, Z = 4; a = 1154.2(6) pm, b = 2291.6(10) pm, c = 1739.9(9) pm, ß = 95.98(5)°] are reported. The green complex transforms into a brown compound at room-temperature; the transformation is (partly) reversibly. Solutions of NCS-anions and Cu²⁺ are redox unstable. The structure of a resulting product: (PPh₄)₂[Cu₂(NCS)₂] [Space group C2/c, Z = 4; a = 1235.4(1) pm, b = 1347.1(2) pm, c = 2953.4(11) pm, ß = 99.36(2)°] with Cu(I) dimers and two bridging NCS^- ligands is also reported.     

Synthesis and Characterization of New Copper(I) Complexes Containing Thione Derivatives of 1, 2, 4‐Triazine. Crystal Structure of [Cu(PPh3)2(ATTO)]NO3 (ATTO = 4‐amino‐1, 2, 4‐triazin‐3(2H)‐thione‐5‐one)

The reaction of 4‐amino‐1, 2, 4‐triazin‐3(2H)‐thione‐5‐one (ATTO, 1 ) with [Cu(PPh₃)₂]NO₃ in ethanol led to the complex [Cu(PPh₃)₂(ATTO)]NO₃ ( 2 ). 2 was characterized by elemental analyses, IR, ¹H NMR and Raman spectroscopy. A single‐crystal X‐ray diffraction of compound 2 revealed that ATTO acts as a bidentate ligand via its nitrogen and sulfur atoms. Crystal data for 2 at 20 °C: space group P2₁/n with a = 975.7(1), b = 1533.5(2), c = 2504.2(3) pm, β = 92.25(1)°, Z = 4, R₁ = 0.0632.     

Untersuchungen an Polyhalogeniden. XVII. Darstellung und Kristallstruktur von Urotropiniumtriiodid,UrHI3

Studies on Polyhalides. 17. Preparation and Crystal Structure of Urotropinium Triiodide, UrHI₃ Urotropinium triiodide C₆H₁₃N₄I₃ is formed by the reaction of equimolar amounts of urotropinium iodide and iodine in ^tBuOH as red-brown cube-like crystals melting at 402 K under decomposition. The compound crystallizes monoclinically in the space group P2₁/c with a = 952.0(3) pm, b = 1 160.2(6) pm, c = 1 149.9(4) pm, β = 92.22(3)° and Z = 4. The till now not described crystal structure (R = 0.027 for 1 860 observed reflexes) contains urotropinium ions UrH⁺ and slightly distorted triiodide ions I₃^?(d(I—I) = 292.3(1), 294.1(1) pm, φ(I—I—I) = 178.27(2)°) which are linked to ion pairs by a rather short contact (d(I …? I) = 389.0(1) pm, φ(I—I …? I) = 149.12(2)°).     

Metallcarbonyl-Synthesen. 23. Kristallstruktur und Reaktionsverhalten von Carbonylmetall-Komplexen des Heptamethylindens

Syntheses of Metal Carbonyls. 23. Crystal Structure and Reactivity of Heptamethylindenyl Carbonyl Metal Complexes Reaction of heptamethylindene (C₉(CH₃)₇, 1 ) with Re₂(CO)₁₀ yields [η⁵-C₉(CH₃)₇]Re(CO)₃ ( 2 ), which reacts with NO⁺BF₄^? to form the cationic complex [{η⁵-C₉(CH₃)₇}Re(CO)₂NO]⁺BF₄^? ( 3 ). Irradiation of 2 with UV light in the presence of triethyl phosphite leads to formation of [η⁵-C₉(CH₃)₇]Re(CO)₂[P(OC₂H₅)₃] ( 4 ). Alkylation of (CH₃)₃SnCl with Ind*Li gives [η¹-C₉(CH₃)₇]Sn(CH₃)₃ ( 5 ). All compounds were characterized by spectroscopic methods. The molecular structures of 3 and 5 were determined by single crystal X-ray diffraction ( 3 : P2₁/n (14), a = 1497.7(4) pm, b = 879.0(2) pm, c = 1609.0(4) pm and β = 110.99(2)°, R₁ = 0.038, wR₂ = 0.080; 5 : P2₁/n (14), a = 726.1(1) pm, b = 2930.7(3) pm, c = 930.0(1) pm and β = 112.834(5)°, R₁ = 0.044, R_w = 0.048). Complexes 2 ? 4 exhibit a piano stool configuration with a η⁵-coordinated permethylindenyl ligand (Ind*). Compound 5 displays a η¹ -coordination of the Ind* ligand. Temperature enhancement causes a hapticity change, as observed by NMR spectroscopy.     

Nanometer Channels and Cages within the Extended Basic Mercurous Cations [(Hg2)3(OH)2]4+ and [(Hg2)2O]2+

The two‐ and three‐dimensional mercurous cations [(Hg₂)₃(OH)₂]⁴⁺ and [(Hg₂)₂O]²⁺ crystallize with channels and cages of roughly 1 nm diameter from aqueous solutions dependent upon the acidity of the solution. Crystal structures were determined, for example, for [Zn(H₂O)₆][(Hg₂)₃(OH)₂](NO₃)₆ (trigonal, space group P321, a = 1183.5(2) pm, c = 534.8(1) pm, Z = 1, R1 = 0.0351 for I₀ > 2σ(I₀)) and for [(Hg₂)₂O][Pb(NO₃)₃]₂ (cubic, space group , a = 1543.1(2) pm, Z = 8, R1 = 0.0534 I₀ > 2σ(I₀)).     

Die Simultanintercalation von Antimonpentachlorid mit einigen Metalltrichloriden in das Graphitgitter

Simultaneous Intercalation of Antimony Pentachloride with Metal Trichlorides into Graphite The metal trichlorides AsCl₃, SbCl₃, BiCl₃, AlCl₃, GaCl₃, and FeCl₃ intercalate simultaneously with SbCl₅ into the graphite lattice forming intercalation compounds of a SbCl₅: MCl₃ ratio between 1:0.16 and 1:4.5. C₂₄SbCl₅(AsCl₃)_0.9 as well as C₆₀SbCl₅(GaCl₃)_4·5 are already formed by a spontaneous intercalation at 25°C. During co-intercalation of SbCl₅ with BiCl₃ and AlCl₃, respectively, the ratios SbCl₅:MCl₃ decrease with increasing intercalation time. X-ray and EPMA measurements suggest that homogeneous mixtures of SbCl₅ and trichlorides are inserted in the interlayer galleries. The identity periods along c-axis of the stage 1 and stage 2 compounds are I_c = 9.30—9.39 Å and I_c = 12.58—12.76 Å, respectively. In stage 1 SbCl₅/AsCl₃-graphite as well as SbCl₅/GaCl₃-graphite a simultaneous desintercalation of SbCl₅ and MCl₃ have been found in vacuum and by solvents. The successive stage increase during thermal deintercalation was investigated by thermogravimetric methods. Mass spectroscopic gas analysis of the pyrolysis products show that the thermal dissociation of SbCl₅ superimposes stage transformations.     

Mono‐ and Dimethyl‐1,2,4‐Triazolate as Ligands for the Mercuric Ion in the Cationic Three‐dimensional Coordination Polymer of [Hg2(Mmt)(Dmt)2](NO3)(H2O)

Colourless crystals of [Hg₂(Mmt)(Dmt)₂](NO₃)(H₂O) were obtained from a reaction of mercuric nitrate with monomethyl‐ and dimethyl‐1,2,4‐triazolate (Mmt^? and Dmt^?, respectively). In the crystal structure (monoclinic, C2/c (no. 15), a = 2579.4(4), b = 1231.1(2), c = 1634.8(2) pm, β = 128.32(1)°, V = 4073.3(11)·10⁶·pm³, Z = 8, R₁ [I₀ > 2σ(I₀)]: 0.0355), half of the mercuric ions are essentially two‐coordinate (Hg–N: 210‐215 pm), the other half are tetrahedrally surrounded by N‐donor atoms (Hg–N: 221, 225 pm) of the Mmt^? and Dmt^? anions. These three‐N ligands construct a three‐dimensional framework.     

Neue Phosphido-verbrückte Mehrkernkomplexe des Ag,Cd und Zn Die Kristallstrukturen von [Ag4(PPh2)4(PMe3)4], [Ag6(PPh2)6(PtBu3)2] und [M4Cl4(PPh2)4(PnPr3)2] (M = Zn,Cd)

New Phosphido-bridged Multinuclear Complexes of Ag, Cd and Zn. The Crystal Structures of [Ag₄(PPh₂)₄(PMe₃)₄], [Ag₆(PPh₂)₆(P^tBu₃)₂] and [M₄Cl₄(PPh₂)₄(PⁿPr₃)₂] (M = Zn, Cd) AgCl reacts with Ph₂PSiMe₃ in the presence of a tertiary Phosphine PMe₃ or P^tBu₃ to form the multinuclear complexes [Ag₄(PPh₂)₄(PMe₃)₄] ( 1 ) and [Ag₆(PPh₂)₆(P^tBu₃)₂] ( 2 ). In analogy to that MCl₂ reacts with Ph₂PSiMe₃ in the presence of PⁿPr₃ to form the two multinuclear complexes [M₄Cl₄(PPh₂)₄(PⁿPr₃)₂] (M = Zn ( 3 ), Cd ( 4 )). The structures were characterized by X-ray single crystal structure analysis ( 1 : space group Pna2₁ (Nr. 33), Z = 4, a = 1 313.8(11) pm, b = 1 511.1(6) pm, c = 4 126.0(18) pm, 2 : space group P–1 (Nr. 2), Z = 2, a = 1 559.0(4) pm, b = 1 885.9(7) pm, c = 2 112.4(8) pm, α = 104.93(3)°, β = 94.48(3)°, γ = 104.41(3)°; 3 : space group C2/c (Nr. 15), Z = 4, a = 2 228.6(6) pm, b = 1 847.6(6) pm, c = 1 827.3(6) pm, β = 110.86(2); 4 : space group C2/c (Nr. 15), Z = 4, a = 1 894.2(9) pm, b = 1 867.9(7) pm, c = 2 264.8(6) pm, β = 111.77(3)°). 3 and 4 may be considered as intermediates on the route towards polymeric [M(PPh₂)₂]_n (M = Zn, Cd).     

Mercuric Bis(N‐imino‐methyl‐formamidate), Hg(Imf)2

Single crystals of mercuric bis(N‐imino‐methyl‐formamidate), Hg(Imf)₂, were obtained from aqueous solutions of 1,2,4‐triazole and Hg(NO₃)₂·2H₂O. The crystal structure [monoclinic, P2₁/c (no. 14), a = 499.6(2), b = 1051.2(4), c = 711.1(3) pm, β = 117.55(1)°, Z = 2, R₁ for 890 reflections with I₀>2σ(I₀): 0.0369] contains linear centrosymmetric Hg(Imf)₂ molecules with Hg–N distances of only 203.5(7) pm. Two plus two intra‐ and intermolecular nitrogen atoms add to an effective coordination number of 6.     

Isotype Borophosphate MII(C2H10N2)[B2P3O12(OH)] (MII = Mg,Mn, Fe,Ni, Cu,Zn): Verbindungen mit Tetraeder‐Schichtverbänden

Isotypic Borophosphates M^II(C₂H₁₀N₂)[B₂P₃O₁₂(OH)] (M^II = Mg, Mn, Fe, Ni, Cu, Zn): Compounds containing Tetrahedral Layers The isotypic compounds M^II(C₂H₁₀N₂) · [B₂P₃O₁₂(OH)] (M^II = Mg, Mn, Fe, Ni, Cu, Zn) were prepared under hydrothermal conditions (T = 170 °C) from mixtures of the metal chloride (chloride hydrate, resp.), Ethylenediamine, H₃BO₃ and H₃PO₄. The orthorhombic crystal structures (Pbca, No. 61, Z = 8) were determined by X‐ray single crystal methods (Mg(C₂H₁₀N₂)[B₂P₃O₁₂(OH)]: a = 936.81(2) pm, b = 1221.86(3) pm, c = 2089.28(5) pm) and Rietveld‐methods (M^II = Mn: a = 931.91(4) pm, b = 1234.26(4) pm, c = 2129.75(7) pm, Fe: a = 935.1(3) pm, b = 1224.8(3) pm, c = 2088.0(6) pm, Ni: a = 939.99(3) pm, b = 1221.29(3) pm, c = 2074.05(7) pm, Cu: a = 941.38(3) pm, b = 1198.02(3) pm, c = 2110.01(6) pm, Zn: a = 935.06(2) pm, b = 1221.33(2) pm, c = 2094.39(4) pm), respectively. The anionic part of the structure contains tetrahedral layers, consisting of three‐ and nine‐membered rings. The M^II‐ions are in a distorted octahedral or tetragonal‐bipyramidal [4 + 2] (copper) coordination formed by oxygen functions of the tetrahedral layers. The resulting three‐dimensional structure contains channels running along [010]. Protonated Ethylenediamine ions are fixed within the channels by hydrogen bonds.     

Präparation,Kristallstruktur, Schwingungsspektren und thermische Analyse von Kupfer‐tetrahydrogen‐decaoxo‐diperiodat‐hexahydrat CuH4I2O10·6H2O

On Copper‐tetrahydrogen‐decaoxo‐diperiodate‐hexahydrate CuH₄I₂O₁₀·6H₂O: Crystal Structure, Vibrational Spectroscopy and Thermal Analysis By crystallization from a strongly acidic aqueous solution copper‐tetrahydrogen‐decaoxodiperiodate‐hexahydrate CuH₄I₂O₁₀· 6H₂O has been obtained. In the structure of this compound (S.G. P 2₁/c, Nr.14), Z = 2, a = 1060.2(2) pm, b = 551.1(1) pm, c = 1164.7(2) pm, β = 111, 49(3)°) centrosymmetric [H₄I₂O₁₀]^2— anions in the form of two edge sharing octahedra form layers via hydrogen bonds originating from the acidic, trans‐configurated OH groups of the anions. Raman spectra are given and analyzed with respect to the internal vibrations of the periodate anion. The dehydration of the compound takes place via CuH₄I₂O₁₀·3H₂O and Cu(H₂IO₅)₂ which decomposes at 170 °C to Cu(IO₃)₂.     

Die Reaktion von SeCl4 mit Übergangsmetalltetrachloriden. Synthese und Kristallstrukturen von (SeCl3)2MCl6 mit M = Zr,Hf, Mo,Re

The Reaction of SeCl₄ with Transition Metal Tetrachlorides. Synthesis and Crystal Structures of (SeCl₃)₂MCl₆ with M = Zr, Hf, Mo, Re The transition metal tetrachlorides ZrCl₄, HfCl₄ and MoCl₄ react with SeCl₄ in closed ampoules at temperatures of 140°C to (SeCl₃)₂MCl₆ (M = Zr, Hf, Mo) which are all isotypic and crystallize in the (SeCl₃)₂ReCl₆ structure type (orthorhombic, Fdd2, Z = 8, lattice constants for M = Zr: a = 1165.7(1)pm, b = 1287.2(2)pm, c = 2180.2(2)pm; for M = Hf: a = 1162.9(2)pm, b = 1285.0(2)pm, c = 2178.2(3)pm; for M = Mo: a = 1153.8(1)pm, b = 1267.7(1)pm, c = 2147.4(2)pm). The Cl^? ions form a hexagonal closest packing with one fourth of the octahedral holes filled by Se⁴⁺ and M⁴⁺ in an ordered way. The MCl₆ octahedra are regular, the SeCl₆ octahedra are distorted with 3 short and 3 long Se? Cl bonds (mean 215 pm and 287 pm). The structures can thus be regarded as built of SeCl₃⁺ and MCl₆^2? ions. Magnetic susceptibility measurements show for M = Zr the expected diamagnetic behavior, for M = Mo and Re paramagnetic behavior according to the Curie-Weiss law with magnetic moments of 2.5 B. M. for M = Mo and 3.7 B. M. for M = Re corresponding to 2 and 3 unpaired electrons respectivly.     

Die Kristallstruktur von PrTe2

The Crystal Structure of PrTe₂ X‐ray diffraction single‐crystal structure analysis of PrTe₂ prepared by chemical vapour transport reactions starting with praseodymium and tellurium in the presence of trace amounts of iodine also revealed superstructure reflections indicating just as for CeTe₂ a (2 × 2 × 2)‐supercell of the basic anti‐Fe₂As‐type structure instead of a (2 × 2 × 1)‐supercell as for LaTe₂. In contrast to LaTe₂ with monoclinic symmetry (space group P1c1), PrTe₂ crystallizes tetragonal in the space group P4 with the lattice parameters a = 896.80(5) pm and c = 1811.9(1) pm (Z = 16). The doubling of the c‐lattice parameter compared to LaTe₂ is observed due to different polyanionic structural motifs in the heights z ≈ 0 and z ≈ ¹/₂. These are a herringbone pattern of [Te₂] dumbbell pairs (motif A; a topology which is also found in LaTe₂), isolated square four‐membered [Te₄] rings in z ≈ 0 (motif B) and additionally rectangular four‐membered [Te₄] rings in z ≈ ¹/₂ (motif C). Though CeTe₂ and PrTe₂ are crystallizing isotypically, there are distinct differences in the interatomic distances within the polyanionic Te layers and resulting from these also a different topology of the structural motif C. The individual structural elements are causing a diffraction pattern, which is all in all to be explained by a statistical superposition of the different elements in form of microdomains.     

Existiert eine Wurtzit‐Modifikation von Lithiumbromid? — Untersuchungen im System LiBr/LiI —

Is there a Wurtzite‐Modification of Lithium Bromide? — Studies on the System LiBr/LiI — Deposition of mixtures of LiBr/LiI (ratio: LiBr/LiI = 3:1, 2:1, 1:1, 1:2, 1:3, 1:4) and of pure LiI and LiBr from the gas phase onto a sapphire substrate at ‐196 °C in a high vacuum chamber were investigated by means of temperature‐dependent X‐ray diffraction. Below 0 °C LiI crystallizes in the hexagonal Wurtzite‐modification (β‐LiI) with a = 451.4(1) und c = 731.1(2) pm, which transforms into the cubic rock salt modification (α‐LiI, a = 602.57(3) pm) by heating up to room temperature. Co‐depositions of LiBr/LiI formed solid LiBr_1‐xI_x solutions that also crystallize in the Wurtzite‐modification, below room temperature. Compared to β‐LiI, these solid solutions are more stable and transform into the cubic phase at the significantly higher temperature of 80 °C. The lattice constants of LiBr_1‐xI_x with x ≈ 0.7 are a = 445.48(7), c = 719.1(1) pm and with x ≈ 0.4 are a = 431.50(5), c = 691.7(1) pm. The hexagonal phase LiBr_1‐xI_x is observed for the complete series of mixed crystals with 0.25 ≤ x ≤ 0.8. Both cubic phases, α‐LiI and LiBr, show solubilities of up to ca. 10 % of the respective other compound. In case of pure LiBr only the cubic modification (a = 551.54(2) pm, 25 °C) was observed in the complete temperature range (‐196 °C to 25 °C).     

Strukturelle Vielfalt im pseudo‐ternären System M/Ge/I: α‐[NMe(nBu)3](GeI4)I, β‐[NMe(nBu)3](GeI4)I und [ImMe(nBu)][N(nBu)4](GeI4)3I2

By reaction of GeI₄, [N(nBu)₄]I as iodide donor, and [NMe(nBu)₃][N(Tf)₂] as ionic liquid, reddish‐black, plate‐like shaped crystals are obtained. X‐ray diffraction analysis of single crystals resulted in the compositions ;alpha;‐[NMe(nBu)₃](GeI₄)I (Pbca; a = 1495.4(3) pm; b = 1940.6(4) pm; c = 3643.2(7) pm; Z = 16) and β‐[NMe(nBu)₃](GeI₄)I (Pn; a = 1141.5(2) pm; b = 953.6(2) pm; c = 1208.9(2) pm; β = 100.8(1)°; Z = 2). Depending on the reaction temperature, the one or other compound is formed selectively. In addition, the reaction of GeI₄ and [N(nBu)₄]I, using [ImMe(nBu)][BF₄] (Im = imidazole) as ionic liquid, resulted in the crystallization of [ImMe(nBu)][N(nBu)₄](GeI₄)₃I₂ (P2₁/c; a = 1641.2(3) pm; b = 1903.0(4) pm; c = 1867.7(4) pm; β = 92.0(1)°; Z = 4). The anionic network of all three compounds is established by molecular germanium(IV)iodide, which is bridged by iodide anions. The different connectivity of (GeI₄–I^–) networks is attributed to the flexibility of I^– regarding its coordination and bond length. Here, a [3+1]‐, 4‐ and 5‐fold coordination is first observed in the pseudo‐ternary system M/Ge/I (M: cation).     

Tl2CuAsO4 – ein Zwischenprodukt bei der Oxidation von Tl/Cu/As-Legierungen im Sauerstoffstrom

Tl₂CuAsO₄ – an Intermediate Phase in the Oxidation of Tl/Cu/As Alloys with Oxygen Waxy, honey-jellow single crystals of the new compound Tl₂CuAsO₄ (monoclinic, P2₁/c, a = 860.1(1) pm, b = 533.94(7) pm, c = 1200.1(2) pm, β = 98.10(1)°, Z = 4) were prepared as an intermediate product of the oxidation process in the reaction of Tl/Cu/As-alloys with oxygen. Their structure was determined from IPDS data (w2R = 0.071 for 1271 F² values and 74 parameters). The structure contains an isolated [Cu₂As₂O₈]^4– group consisting of two AsO₄-tetrahedra connected by two Cu⁺ ions with an approximately linear O–Cu–O coordination. The [Cu₂As₂O₈]^4– groups are linked to a threedimensional framework by thallium(I) ions which show an hemispheric coordination sphere of oxygen ions indicating the stereochemical activity of the Tl⁺ lone pair.     

Crystal structure of a new insertion compound formed by PdCl2 and tri-methylamine [(CH3)3NH]2PdCl4.(CH3)3NHCl

The complex 3[(CH₃)₃NHCl].pdCl₂ crystallises in the orthorhombic system, space group Pnma: a = 990(1) pm; b = 1209(1) pm; c = 1721(2) pm; Z = 4; d_th = 1.49; d_exp = 1.45. The structure is composed of square planar PdCl₄²⁻ ions (average length PdCl = 230 pm), of two ammonium groups, each one equidistant of two chlorine atoms and in cis position to the plane of PdCl₄²⁻. A third (CH₃)₃NHCl molecule is in insertion in the structure. This is a new type of solvate in which the insertion molecule is an ion pair.     

Das prismatische Te62+-Ion in der Struktur von Te6(NbOCl4)2

The Prismatic Te₆²⁺ Ion in the Structure of Te₆(NbOCl₄)₂ Te₆(NbOCl₄)₂ is obtained from Te, TeCl₄ and NbOCl₃ at 200°C. It crystallizes triclinic, space group P1 (a = 915,5(4) pm, b = 1655,3(6) pm, c = 3134,4(9) pm, α = 42,62(2)°, β = 117,12(6)°, γ = 138,24(8)°). The crystal structure analysis shows, that the structure is built of one-dimensional polymeric [NbOCl₄^?] chains in which the monomers are linked via linear O? Nb? O-bridges and from discrete Te₆²⁺ polycations that are also arranged in strands, but without significant interactions. The structure is closley related but not isotypic to the previously reported tungsten containing analogue Te₆(WOCl₄)₂ (monoclinic, P2₁/c). A comparison of the two structures shows that rotations of the cationic strands relative to the anionic strands lead to different cation-anion interactions.