Ln2XCHy: Kondensierte Cluster mit zwei verschiedenen interstitiellen Atomen

Ln₂XCH_y: Condensed Clusters with Two Different Interstitial Atoms Lanthanide carbide hydride halides Ln₂XCH_y(Ln = Gd, Tb; X = Cl, Br, I; y_max = 1) are obtained by heating Ln₂XC in H₂ at 820 K. Via this reversible, topochemical reaction two different interstitial species can be incorporated at will into a condensed cluster compound for the first time. The inclusion of H is accompanied by a change from the M₆X₁₂ to the M₆X₈ cluster type. With increasing hydrogen content, electrons are gradually localized from metal—metal bonding in H-centered states finally leading to a metal-semiconductor transition. The magnetic ordering Temperatures are lowered in comparison to Ln₂XC. Hydrogenation and dehydrogenation were studied by X-ray and resistivity investigations.     

Trigonal-bipyramidale Cluster mit interstitiellen C2-Hanteln in den Chloriden K[M5(C2)]Cl10 (M = La,Ce, Pr) und Rb[M5(C2)]Cl10 (M = Pr,Nd)

Trigonal-Bipyramidal Clusters with Interstitial C₂-Units in the Chlorides K[M₅(C₂)]Cl₁₀ (M = La, Ce, Pr) and Rb[M₅(C₂)]Cl₁₀ (M = Pr, Nd) The chlorides K[M₅(C₂)]Cl₁₀ (M = La, Ce, Pr) and Rb[M₅(C₂)]Cl₁₀ (M = Pr, Nd) are obtained via metallothermic reduction of the trichlorides MCl₃ with potassium and rubidium, respectively, in the presence of metal M and carbon in sealed niobium containers at temperatures between 700 and 900°C. They contain trigonal bipyramids, interstitially stabilized by a C₂ unit, [M₅(C₂)], and crystallize with the hexagonal (K[Pr₅(C₂)]Cl₁₀, Rb[M₅(C₂)]Cl₁₀ with M = Pr, Nd) or monoclinic (K[M₅(C₂)]Cl₁₀ with M = La, Ce) crystal system. The trigonal bipyramids are surrounded by nine inner Cl^? ligands (capping the nine edges) and by 12 (hexagonal) or 13 (monoclinic) outer ligands and are connected via all of the 21 and 22 ligands, respectively. Special features are Cl^a-a-a (hexagonal) and Cl^a-a-a-a (monoclinic) bridges.     

[M9C4O]I8 (M = Y,Ho, Er,Lu), reduzierte Selten-Erd-Iodide mit gewellten Metall-Doppelschichten und zwei verschiedenen interstitiellen Atomen

[M₉C₄O]I₈ (M = Y, Ho, Er, Lu), Reduced Rare-Earth Iodides with Waved Metal Double Layers and Two Different Interstitial Atoms [M₉C₄O]I₈ (M = Y, Ho, Er, Lu) are examples of reduced rare-earth iodides with two different interstitial atoms. The compounds were synthesized from appropriate mixtures of MI₃, M, C and M₂O₃ at 1 050°C in arc-welded tantalum containers. The X-ray structure analysis of a single crystal of [Y₉C₄O]I₈ (orthorhombic, Pmmn (Nr. 59), Z = 2, a = 2 912.7(6) pm, b = 384.17(4) pm, c = 1 080.29(9) pm, R = 0.084, R_w = 0.053) exhibits octahedrally coordinated carbon in “plane” sections besides tetrahedrally coordinated oxygen in the “bend” of waved metal double layers. These double layers are stacked alternately with waved iodine double layers along [001].     

RuS4Cl12 und Ru2S6Cl16, zwei neue Ruthenium(II)‐Komplexe mit SCl2‐Liganden

RuS₄Cl₁₂ and Ru₂S₆Cl₁₆, Two New Ruthenium(II) Complexes with SCl₂ Ligands Ru powder was reacted with SCl₂ in closed silika ampoules at 140 °C. From the black solution three compounds RuS₄Cl₁₂ 1 , Ru₂S₆Cl₁₆ 2 , and Ru₂S₄Cl₁₃ 3 could be crystallized and characterized by x ray analysis. Black crystals of 1 (monoclinic, a = 9.853(1) Å, b = 11.63(1) Å, c = 15.495(1) Å, β = 105.23(1)°, space group P2₁/c, z = 4) are identified as Trichlorsulfonium‐tris(dichlorsulfan)trichloro‐ruthenat(II) SCl₃[RuCl₃(SCl₂)₃]. In the structure the complex anions fac‐[RuCl₃(SCl₂)₃]^– and the cations [SCl₃]⁺ are connected to ion pairs by three chlorine bridges. The brown crystals of 2 (triclinic, a = 7.754(2) Å, b = 7.997(2) Å, c = 10.708(2) Å, α = 103.74(3)°, β = 98.44(3)°, γ = 108.58(3)°, space group P‐1, z = 1) contain the binuclear complex Bis‐μ‐chloro‐dichloro‐hexakis(dichlorsulfan)‐diruthenium(II), (SCl₂)₃ClRu(μ‐Cl)₂RuCl(SCl₂)₃ with two fac‐RuCl₃(SCl₂)₃‐units connected by two chlorine bridges. 3 was identifyed as a known mixed valence Ru(II,III) binuclear complex [Cl₂(SCl₂)Ru(μ‐Cl)₃Ru(SCl₂)₃]. The vibrational spectra and the thermal behaviour of the compounds are discussed.     

Gd4I6CN: Ein Carbidnitrid mit Ketten aus Gd6(C2)-Oktaedern und Gd6N2-Tetraederdoppeln

Gd₄I₆CN: A Carbide Nitride with Chains of Gd₆(C₂) Octahedra and Gd₆N₂ Double Tetrahedra The compound α-Gd₄I₆CN is prepared by reaction of Gd, GdI₃, C, and GdN (1:2:1:1 mole ratio) at 1 170 K in sealed Ta tubes. It is obtained as brown red, transparent needles which are air and moisture sensitive. The structure of α-Gd₄I₆CN contains Gd₆ octahedra centered by C₂ groups and double tetrahedra centered by N atoms. The units are alternatingly connected via common edges to form chains (Gd₂Gd_4/2C₂) (Gd_2/2Gd_2/2N)₂ parallel [001]. The linear chains are surrounded by I atoms above all free edges of the metal polyhedra and linked according to (Gd₂Gd_4/2C₂) (Gd₂Gd_4/2N₂)I_4/2I₈I₂ in the a – b plane. We also found β-Gd₄I₆CN, which is formed in a monotropic transition from the α-form. In the structure the chains of Gd octahedra and tetrahedra as described for α-Gd₄I₆CN are more densely packed. The structure of Y₆I₉C₂N is composed by chains of pairs of Y-octahedra and Y-tetrahedra, respectively. The octahedra are centered by C₂ groups, the tetrahedra by N-atoms. We also synthesized the compounds Gd₄Br₆CN und La₄I₆CN by tempering at 1 220 K. They are isotypic with α-Gd₄I₆CN.     

Die Gadoliniumcarbidhalogenide Gd4C2X3 (X = Cl,Br)

The Gadolinium Carbide Halides, Gd₄C₂X₃ (X = Cl, Br) The compounds Gd₄C₂X₃ (X = Cl, Br) and Tb₄C₂Br₃ have been prepared by reaction of the metals (RE), REX₃, and C in sealed Ta capsules at 1 100° and 1 300°C, respectively. Monophasic samples of Gd₄C₂Br₃ and Tb₄C₂Br₃ were obtained by reacting stoichiometric mixtures of the starting materials for five days. The needle shaped crystals are bronze-coloured and sensitive to air and moisture. Gd₄C₂X₃ crystallizes in the space group Pnma (No. 62) with lattice constants a = 1 059.6(4), b = 368.4(1), c = 1 962.7(8) pm (Gd₄C₂Cl₃), a = 1 084.4(1), b = 373.0(1), c = 2 036.1(1) pm (Gd₄C₂Br₃). According to Guinier photographs, Tb₄C₂Br₃ is isotypic (a = 1 074.3(2), b = 370.6(1), c = 2 019.4(1) pm). In the crystal structure C is octahedrally coordinated by Gd. The Gd₆ octahedra are linked via common edges to form corrugated layers. The X-anions coordinate all free edges and corners of these layers and connect them via Xⁱ? Xⁱ contacts parallel [001]. Gd₄C₂Br₃ shows metallic conductivity. The magnetic susceptibility follows at high temperatures a Curie Weiss law with an effective moment of 7.95 μ_B. At temperatures below 50 K antiferromagnetic order is observed.     

Weitere metastabile Verbindungen mit Tunnelstruktur BaCa2Er10O18 und BaCa2Yb10O18

Single crystals of the unknown compounds BaCa₂Er₁₀O₁₈ (A) and BaCa₂Yb₁₀O₁₈ (B) were prepared by a high-temperature CO₂-laser technique and investigated by X-ray work. (A) and (B) are metastable compounds with an Ln₁₀O₁₈⁶⁻ framework. Two types of tunnels built up by this framework are occupied statistically and in a disordered manner by Ba²⁺, Ca²⁺ and Ln³⁺ ions. The relationship with compounds of the formula AB₂Ln₆O₁₂ are discussed.     

Cs3[Tb10(C2)2]Cl21, ein neuer Formel- und Strukturtyp mit isolierten,dimeren Clustern

Cs₃[Tb₁₀(C₂)₂]Cl₂₁, A New Formula and Structure Type with Isolated Dimeric Clusters Cs₃[Tb₁₀(C₂)₂]Cl₂₁ is obtained via the metallothermic reduction of TbCl₃ with caesium in the presence of graphite as black single crystals. The crystal structure (monoclinic, C2/c, Z = 4; a = 2318.72(13); b = 1245.8(9); c = 1502.0(13) pm; β = 98.13(6)°; R = 0.089; R_w = 0.049) contains dimeric clusters that are built from two octahedra connected via one common edge and filled with C₂ units. These isolated [Tb₁₀(C₂)₂] clusters are surrounded by 26 chloride ligands which are then connected via i—a and a—a bridges in a way that voids for Cs⁺ of coordination number 10 are formed.     

Gd12C6I17 – eine Verbindung mit kondensierten,C2-gefüllten Gd6I12-Clustern

Gd₁₂C₆I₁₇ — a Compound with Condensed, C₂-Containing Gd₆I₁₂ Clusters Gd₁₂C₆I₁₇ was isolated in black shining crystals from a reaction product of Gd, GdI₃ and graphite, heated in sealed tantalum capsules at 1170 K. The compound is monoclinic (C2/c; a = 1929.7(9), b = 1220.1(5), c = 1863.5(5) pm, = 90.37(3)°). The crystal structure is composed of linear units of 3 condensed Gd₆I₁₂ clusters (connection via trans-edges of the central Gd₆ octahedron), which are further linked via cis edges to form zig-zag chains. The centres of the Gd₆ octahedra are occupied by C₂ units. The distances d_{C? C} ≈ 145 pm correspond to a filling of the antibonding π* orbitals of the C₂ group, which, however, interact with empty d-orbitals of the metal atoms especially in the apices of the octahedra and thus loose their pure carbon character. The short Gd? C distances (d_{Gd? C} = 222 and 227 pm, respectively) are explained as due to multiple bonds. The occurrence of C₂ units and single C atoms, respectively, in lanthanide carbides and carbide halides is coupled to the electron concentration of the metal or cluster framework.     

Zum chemischen Transport von ZrO2 und HfO2 mit den Transportmitteln Cl2 und TeCl4

On the Chemical Transport of ZrO₂ and HfO₂ with the Transport Agents Cl₂ and TeCl₄ ZrO₂ und HfO₂ migrate in a temperature gradient (1100 → 1000°C) with the transport agent either Cl₂ or TeCl₄ by endothermic transport reaction. At experiments in silica glass tubes with TeCl₄ well developed crystals of ZrO₂ could be obtained. From HfO₂, as from both oxides using Cl₂, only powdery products are formed. The transport rates with TeCl₄ were higher than with Cl₂. The influence of different pressures was examined for the transport of ZrO₂ with TeCl₂ with thermochemical model calculations the expected transport rates could be investigated. The large correspondence between calculated and experimental received values speaks for a true interpretation of the transport observations.     

Chlorination of Two Isomers of C86 Fullerene: Molecular Structures of C86(16)Cl16, C86(17)Cl18, C86(17)Cl20, and C86(17)Cl22

Chlorination of a mixture of C₈₆ isomers no. 16 (C_s) and no. 17 (C₂) with VCl₄ or a (TiCl₄+Br₂) mixture afforded crystalline chlorides with 16 to 22 Cl atoms per fullerene cage. Single crystal X‐ray diffraction with the use of synchrotron radiation enabled us to determine the chlorination patterns of C₈₆(16)Cl₁₆, C₈₆(17)Cl₁₈, C₈₆(17)Cl₂₀, and C₈₆(17)Cl₂₂. At these degrees of chlorination, addition patterns of C₈₆(16) and C₈₆(17) chlorides have some features in common, owing to the close similarity in the cage structures of both isomers. The average energy of C?Cl bonds decreases with increasing number of attached Cl atoms.     

Die Reaktion von Quarzglas mit Al2Cl6,g und mit Alrf + Al2Cl6,g

Reaction of Quartz Glass with Al₂Cl_6,g and with Al,_f + Al₂Cl_6,g The attack of quartz glass by Al₂Cl_6,g at temperatures ≧ 300°C results in the formation of SiCl_4,g. At low temperature the oxygen appears as gaseous oxide chloride (e. g. Al₄OCl₁₀…); above 300°C crystalline AlOCl is observed, whereas at more elevated temperatures Al₂O₃ is formed. With Al + Al₂Cl₆ (1 atm, 20°C) at 400/350°C thin silicon foils with metallic luster deposit on the quartz wall. Discussion of the experimental evidence leads to the suggestion that the reduction of SiCl₄ — formed initially by attack of the quartz vessel — proceeds by reaction with Al₂Cl_4,g.     

Metalloktaederdoppel in den Clusterverbindungen Gd10I16(C2)2 und Gd10Br15B2/Tb10Br15B2

Gd₁₀I₁₆(C₂)₂ and Gd₁₀Br₁₅B₂/Tb₁₀Br₁₅B₂ Cluster Compounds with M₁₀ Twin Octahedra The compound Gd₁₀I₁₆(C₂)₂ can be prepared from Gd metal, GdI₃ and C at 950 °C. It crystallizes in P1 with a = 10.463(4) Å, b = 16.945(6) Å, c = 11.220(4) Å, α = 99.15(3)°, β = 92.68(3)° und γ = 88.06(3)°. Gd₁₀Br₁₅B₂ is formed between 900 und 950 °C, Tb₁₀Br₁₅B₂ between 900 und 930 °C from stoichiometric amounts of the rare earth metals, tribromide and boron. Both compounds crystallize in the space group P1 for Gd₁₀Br₁₅B₂ with a = 8.984(2) Å, b = 9.816(2) Å, c = 10.552(5) Å, α = 91.14(3)°, β = 114.61(3)° and γ = 110.94(3)° and for Tb₁₀Br₁₅B₂ with a = 8.939(4) Å, b = 9.788(3) Å, c = 10.502(2) Å, α = 91.19(3)°, β = 114.51(3)° and γ = 111.10(2)°. In the crystal structures of all three compounds the rare earth metals form edge‐shared Ln₁₀ twin octahedra. In Gd₁₀I₁₆(C₂)₂ the Gd octahedra are centered with C₂ groups (d_C–C = 1.43(7) Å). In Ln₁₀Br₁₅B₂ (Ln = Gd, Tb) the octahedra contain single boron atoms. The clusters are connected through halide atoms to chains [Ln₁₀(Z)₂X X X ]. Adjacent chains are fused threedimensionally via I I for the Gd iodide carbide and via Br Br for the bromide borides of Gd und Tb. It is interesting to see an identical pattern of connection between the chains for the reduced oxomolybdates, e. g. PbMo₅O₈.     

Neue Komplexe der Lanthanoiden mit zweizähnigen Liganden. Die Strukturen von [(C17H17N2)GdBr2(thf)2] und [(C17H17N2)3Ln] (L = Sm,Gd)

New Complexes of the Lanthanoides with Bidentate Ligands. The Crystal Structures of [(C₁₇H₁₇N₂)GdBr₂(thf)₂] and [(C₁₇H₁₇N₂)₃Ln] (L = Sm, Gd) Reaction of [(AIP)Li] with GdBr₃ leads to a new mononuclear complex [(AIP)GdBr₂(thf)₂] 1 . In contrast to this with SmI₂ the compound [(AIP)₃Sm] 2 is build up. Such complexes are also formed with Gd(OR^*)₃ (R^* = O^tBu₂C₆H₃) and [(AIP)Li] in a 1:3 ratio, [(AIP)₃Gd] 3 . The structures of 1–3 were characterized by X-ray single crystal structure analysis ( 1 : space group Pna2₁ (No. 33), Z = 4, a = 1 972.7(9) pm, b = 984.7(5) pm, c = 1 425.0(8) pm, α = β = γ = 90°; 2 · 2 THF: space group C2/c (No. 15), Z = 8, a = 3 644.4(9) pm, b = 1 437.5(5) pm, c = 2 334.4(7) pm, β = 1 21.07(6)°; 3 : space group P2(1)/c (No. 14), Z = 4, a = 1 872.9(1) pm, b = 1 064.6(1) pm, c = 2 282.4(2) pm, β = 103.75(8)°).     

Molybdänhalogenidcluster mit zwei terminalen Alkoholatliganden: Synthese und Kristallstrukturen von (C18H36N2O6Na)2[Mo6Cl12(OCH3)2] und (C18H36N2O6Na)2[Mo6Cl12(OC15H11)2] · 2C4H6O3

Molybdenum(II) Halide Clusters with two Alcoholate Ligands: Syntheses and Crystal Structures of (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OCH₃)₂] and (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OC₁₅H₁₁)₂] · 2C₄H₆O₃ . Reaction of Mo₆Cl₁₂ with two equivalents of sodium methoxide in the presence of 2,2,2-crypt yields (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OCH₃)₂] ( 1 ), which can be converted to (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OC₁₅H₁₁)₂] · 2C₄H₆O₃ ( 2 ) by metathesis with 9-Anthracenemethanole in propylene carbonate. As confirmed by X-ray single crystal structure determination ( 1 : C2/m, a=25.513(8) Å, b=13.001(3) Å, c=10.128(3) Å, β=100.204(12)°; : C2/c, a=15.580(5) Å, b=22.337(5) Å, c=27.143(8) Å, β=98.756(10)°) the compounds contain anionic cluster units [Mo₆ClCl(OR^a)₂]^2? with two alcoholate ligands in terminal trans positions ( 1 : d(Mo—Mo) 2.597(2) Å to 2.610(2) Å, d(Mo—Clⁱ) 2.471(3) Å to 2.493(4) Å, d(Mo—Cl^a) 2.417(8) Å and 2.427(8) Å, d(Mo—O) 2.006(13) Å; 2 : d(Mo—Mo) 2.599(3) Å to 2.628(3), d(Mo—Clⁱ) 2.468(8) Å to 2.506(7) Å, d(Mo—Cl^a) 2.444(8) Å and 2.445(7) Å, d(Mo—O) 2.012(19) Å).     

Pr6C2‐Doppeltetraeder in Pr6C2Cl10 und Pr6C2Cl5Br5

Pr₆C₂‐Bitetrahedra in Pr₆C₂Cl₁₀ and Pr₆C₂Cl₅Br₅ The compounds Pr₆C₂Cl₁₀ and Pr₆C₂Cl₅Br₅ are prepared by heating stoichiometric mixtures of Pr, PrCl₃, PrBr₃ and C in sealed Ta capsules at 810 ? 820 °C. They form bulky transparent yellow to green and moisture sensitive crystals which have different structures: space groups C2/c, (a = 13.687(3) Å, b = 8.638(2) Å, c = 15.690(3) Å, β = 97.67(3)° for Pr₆C₂Cl₁₀ and a = 13.689(1) Å, b = 10.383(1) Å, c = 14.089(1) Å, β = 106.49(1)° for Pr₆C₂Cl₅Br₅). Both crystal structures contain C‐centered Pr₆C₂ bitetrahedra, linked via halogen atoms above edges and corners in different ways. The site selective occupation of the halogen positions in Pr₆C₂Cl₅Br₅ is refined in a split model and analysed with the bond length‐bond strength formalism. The compound is further characterized via TEM investigations and magnetic measurements (μ_eff = 3.66 μ_B).