Selten-Erd-Hydrogensulfate M(HSO4)3 (M = La,Ce–Nd): Derivate des UCl3-Typs

Rare Earth Hydrogensulfates M(HSO₄)₃ (M = La, Ce–Nd): Derivatives of the UCl₃ Type of Structure Hydrogensulfates of the lighter lanthanides are obtained from the reaction of the respective anhydrous sulfates with conc. sulfuric acid at 200 °C. According to X-ray single crystal determinations on La(HSO₄)₃ (hexagonal, P6₃/m, a = 945.64(9) pm, c = 590.87(5) pm), Ce(HSO₄)₃ (a = 943.34(10) pm, c = 587.88(5) pm), Pr(HSO₄)₃ (hexagonal, P6₃/m, a = 939.8(1) pm, c = 584.82(9) pm) and Nd(HSO₄)₃ (hexagonal, P6₃/m, a = 935.67(8) pm, c = 582.36(4) pm) they all crystallize analogous to the UCl₃ type of structure with nine-coordinate M³⁺ ions. The OH groups of the [HOSO₃]^– ”︁tetrahedra”︁”︁ build up channels parallel [00.1] typical for this type of structure. Hydrogen bonding, however, is only weak in these compounds.     

Sulfidchloride (MSCl) der leichten Lanthanide (M = La–Pr)

Sulfide Chlorides (MSCl) of the Light Lanthanides (M = La–Pr) The reactions of the light lanthanides (M = La–Nd) with sulfur and the respective trichlorides (MCl₃) in evacuated silica tubes (850 °C, 7 d) yield single-phase sulfide chlorides of the composition MSCl when appropriate molar ratios (2 : 3 : 1) of the reactants (M : S : MCl₃) are used. A slight excess of trichloride as a flux promotes the formation of lath-shaped transparent single crystals (colorless for M = La and Ce, apple-green for M = Pr) which prove to be water soluble and sensitive to hydrolysis. The crystal structure was determined from X-ray single-crystal data taking LaSCl (orthorhombic, Pbcm (no. 57), a = 680.22(5), b = 705.26(7), c = 4203.7(3) pm, Z = 24, R = 0.069, R_w = 0.043) as an example. According to Guinier powder data CeSCl and quickly quenched samples of PrSCl crystallize isotypically. Thus four crystallographically independent cations (M³⁺) are present, each coordinated by four S^2– but differing in the number of their next Cl^– neighbors. The figures of coordination are completed by four Cl^– about M1 (square antiprism, CN = 8), by only two Cl^– about M2 (trigonal prism, CN = 6), and by three Cl^– each about M3 and M4 (capped trigonal prisms, CN = 7). Six crystallographically different anions, although indistinguishable by X-ray diffraction, exhibit coordination numbers of four (S^2–, 3 ×) and three (Cl^–, 3 ×) with respect to the cations. So PbO-analogous layers of the composition [SM_4/4]⁺ parallel (100) are formed and held together along [100] by alternatingly sheathed Cl^– layers.     

Eu(ClO4)3: First Single Crystals of an Anhydrous Rare‐Earth Perchlorate

Single crystals of Eu(ClO₄)₃ have been obtained by slow dehydration of a hydrous product prepared by the reaction of Eu₂O₃ with HClO₄. The crystal structure (hexagonal, P6₃/m, Z = 2, a = 924.96(9), c = 574.86(8) pm) consists of tricapped trigonal [EuO₉] prisms and [ClO₄] tetrahedra. One of the oxygen atoms in the ClO₄ group does not coordinate to Eu³⁺ and points towards the empty channel which runs in the direction [001].     

Darstellung und Aufbau der Lanthanoidfluorid‐catena‐Trisilicate M3F[Si3O10] (M = Dy,Ho, Er) im Fluorthalenit‐Typ (Y3F[Si3O10])

Synthesis and Constitution of Fluorothalenite‐Type (Y₃F[Si₃O₁₀]) Fluoride catena‐ Trisilicates M₃F[Si₃O₁₀] with the Lanthanides (M = Dy, Ho, Er) By the reaction of the sesquioxides M₂O₃ with the corresponding trifluorides MF₃ (M = Dy, Ho, Er), SiO₂ and CsCl as flux (molar ratio: 1 : 1 : 3 : 6; 700 °C, 7 d) in evacuated silica tubes and gastight sealed metal capsules made of platinum, niobium or tantalum, respectively, single crystals of the fluoride silicates M₃F[Si₃O₁₀] (monoclinic, P2₁/n; Z = 4; M = Dy: a = 734.06(6), b = 1116.55(9), c = 1040.62(8) pm, β = 97.281(7)°; M = Ho: a = 730.91(6), b = 1111.68(9), c = 1037.83(8) pm, β = 97.238(7)°; M = Er: a = 727.89(6), b = 1107.02(9), c = 1035.21(8) pm, β = 97.209(7)°) were obtained. The most important building groups in the crystal structures of the thalenite type are “isolated” [FM₃]⁸⁺ triangles and catena‐trisilicate anions [Si₃O₁₀]^8–, which contain three [SiO₄] tetrahedra linked to a chain fragment via common corners. This has the shape of a horseshoe where both the terminal tetrahedra show different conformations (eclipsed and staggered) relative to the central unit. Therefore a chelatizing coordination on the same M³⁺ cation via oxygen atoms of both terminal [SiO₄] groups is possible. The narrow area of existence of these fluoride silicates within the lanthanide series will be discussed and structural comparisons with other catena‐trisilicates are presented.     

Neue thermische Abbauprodukte von Ln2CeMO6Cl3 (M = Nb,Ta; Ln = La–Sm) – Darstellung von strukturverwandtem (La, Tb)3,5TaO6Cl4–x

Contributions on the Investigation of Inorganic Nonstoichiometric Compounds. XLV. New Thermal Decomposition Products of Ln₂CeMO₆Cl₃ – Preparation of Structure‐related (La, Tb)_3.5TaO₆Cl_4–x The thermal decomposition (T £ 900–1050°C) of Ln₂CeMO₆Cl₃ (M = Nb, Ta; Ln = La, Ce, Pr, Nd, Sm) leads to the formation of two mixed‐valenced phases (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ‘‘AB”︁”︁) and (Ln, Ce)_3.5MO₆Cl_4–x (phase ‘‘BB”︁”︁) and to the formation of chlorine according to redox‐reactions between Ce⁴⁺ and Cl^–. Single crystals of both phases (Ln, Ce)_3.25MO₆Cl_3.5–x (‘‘AB”︁”︁) and (Ln, Ce)_3.5MO₆Cl_4–x (‘‘BB”︁”︁) were obtained by chemical transport reactions using both powder of Ln₂CeMO₆Cl₃ (phase ‘‘A”︁”︁) and powder of (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ‘‘AB”︁”︁) as starting materials and chlorine (p{Cl₂; 298 K} = 1 atm) or HCl (p{HCl; 298 K} = 1 atm) as transport agent. A crystal of (La, Ce)_3.25NbO₆Cl_3.5–x (”︁AB”︁”︁) (space group: C2/m, a = 35.288(1) Å, b = 5.418(5) Å, c = 9.522(1) Å, β = 98.95(7)°, Z = 4) was investigated by x‐ray diffraction methods, a crystal of (Pr, Ce)_3.5NbO₆Cl_4–x (”︁BB”︁”︁) was investigated by synchrotron radiation (λ = 0.56 Å) diffraction methods. The lattice constants are a = 18.863(6) Å, b = 5.454(5) Å, c = 9.527(6) Å, β = 102.44(3)° and Z = 4. Structure determination in the space group C2/m (No. 12) let to R1 = 0.0313. Main building units are NbO₆‐polyhedra with slightly distorted trigonally prismatic environment for Nb and chains of face‐sharing Cl₆‐octahedra along [010]. The rare earth ions are coordinated by chlorine and oxygen atoms. These main structure features confirmed the expected relation to the starting material Ln₂CeMO₆Cl₃ (phase ”︁A”︁”︁) and to (Ln, Ce)_3.25MO₆Cl_3.5–x (phase ”︁AB”︁”︁).     

Über die Oxidsilicate M2O[SiO4] der schweren Lanthanoide (M = Dy–Lu) im A‐Typ

On the Oxide Silicates M₂O[SiO₄] of the Heavy Lanthanides (M = Dy–Lu) with the A‐Type Structure By reacting the sesquioxides M₂O₃ of the heavy lanthanides (M = Dy–Lu) with SiO₂ and CsCl as flux (molar ratio 1 : 1 : 4; 700 °C, 7 d) in evacuated silica ampoules, it is possible to expand the series of lanthanide oxide silicates M₂O[SiO₄] with the A‐type structure (to date known with M = La–Tb) down to lutetium. The most important structural features, besides isolated ortho‐silicate anions [SiO₄]^4–, form oxygen‐centred (M³⁺)₄ tetrahedra, which are condensed to a two‐dimensional network [O(M1)_1/1(M2)_3/3)]⁴⁺ by sharing common edges and corners. The adaption of the structure (with coordination numbers of seven and nine, respectively, for the M³⁺ cations) to the smaller ionic radii of the heavy lanthanides is shown with help of X‐ray single‐crystal data. The influence of temperature on the stability of the products will be discussed.     

Über Oxidtelluride (M2O2Te) der leichten Lanthanide (M = La–Nd,Sm–Ho) im A-Typ mit anti-ThCr2Si2-Struktur

On Oxytellurides (M₂O₂Te) of the Early Lanthanides (M = La–Nd, Sm–Ho) with A- or anti -ThCr₂Si₂-Type Crystal Structure By reacting elementary lanthanide metal (M = La–Nd, Sm–Ho) with tellurium dioxide (TeO₂) in a 2 : 1 molar ratio, it is possible to obtain pure and single-phase oxytellurides of the composition M₂O₂Te at 750 °C in evacuated silica tubes within a few days. When larger quantities of cesium chloride (CsCl) are added as flux, plate-like single crystals with square cross-section are formed which are not sensitive to hydrolysis and very suitable for crystal structure refinements from X-ray data. In the anti-ThCr₂Si₂ analogous crystal structure (tetragonal, I4/mmm, Z = 2; La₂O₂Te: a = 412.31(4), c = 1309.6(1) pm; Ce₂O₂Te: a = 408.17(4), c = 1294.7(1) pm; Pr₂O₂Te: a = 405.62(4), c = 1285.8(1) pm; Nd₂O₂Te: a = 403.08(4), c = 1277.1(1) pm; Sm₂O₂Te: a = 399.83(4), c = 1265.5(1) pm; Eu₂O₂Te: a = 397.56(4), c = 1257.9(1) pm; Gd₂O₂Te: a = 396.20(4), c = 1253.2(1) pm; Tb₂O₂Te: a = 393.89(4), c = 1245.4(1) pm; Dy₂O₂Te: a = 392.34(4), c = 1240.3(1) pm; Ho₂O₂Te: a = 390.57(6), c = 1239.0(3) pm) the M³⁺ cations are surrounded by nine anions (4 O^2– und 4 + 1 Te^2–) in the shape of a capped square antiprism. The anions show coordination numbers of four (O^2–: tetrahedra) and eight plus two (Te^2–: bicapped cubes) with respect to the cations. PbO-analogous square {[OM_4/4]₂}²⁺ triple layer slabs are present parallel (001), which originate through two-dimensional infinite linking of [OM₄]¹⁰⁺ tetrahedra via two trans-orientated pairs of edges (i. e. four edges altogether). These cationic layers are piled alternatingly along [001] with likewise quadratic single layers of Te^2– anions, which take care of the three-dimensional coherence as well as of the charge balance.     

Synthesis,Crystal Structure,and Thermal Behavior of Pr(ClO3)3 · 2 H2O

Single crystals of Pr(ClO₃)₃ · 2 H₂O have been obtained from the reaction of Pr₂(CO₃)₃ · x H₂O and HClO₃. The crystal structure (orthorhombic, P2₁2₁2₁, Z = 4, a = 576.03(7), b = 1236.7(2), c = 1314.0(2) pm) contains Pr³⁺ ions coordinated by two H₂O molecules and seven ClO₃^– groups. According to DTA/TG measurements, Pr(ClO₃)₃ · 2 H₂O decomposes in a two step mechanism with Pr(ClO₃)₃ as an intermediate and PrOCl as the final product. The decomposition has also been investigated by means of temperature dependent X-ray powder diffraction.     

Stabilisierung von M+‐Ionen (M = In,Tl) durch Dibenzyldichlorogallat

Stabilization of M⁺ Ions (M = In, Tl) by Dibenzyldichlorogallate MCl reacts with (PhCH₂)₂GaCl to give M[(PhCH₂)₂GaCl₂] [M = In ( 1 ), Tl ( 2 )]. 1 and 2 were characterized by NMR, IR and MS techniques. In addition, an X‐ray structure determination of 1 was performed. According to this, 1 consists of four‐membered In₂Cl₂ rings connected by weak In…Cl contacts (344 pm) along [010] to a coordination polymer. The In⁺ ion is coordinated by four In–Cl and two In‐aryl interactions.     

Bismut(II)-chalkogenometallate(III) Bi2M4X8, Verbindungen mit Bi24+-Hanteln (M = Al,Ga; X = S,Se)

Bismuth(II) Chalcogenometallates(III) Bi₂M₄X₈, Compounds with Bi₂⁴⁺ Dumbbells (M = Al, Ga and X = S, Se) The ternary bismuth(II) chalcogenometallates(III) Bi₂M₄X₈ (with M = Al, Ga and X = S, Se) were synthesized from the binary chalcogenides M₂X₃ and Bi₂X₃ and elementary bismuth. All compounds are diamagnetic semiconductors with E_g (opt.) = 1.8–2.7 eV. The phases (except Bi₂Al₄Se₈) are thermodynamically stable and decompose peritectically above 965–1020 K. Bi₂Al₄Se₈ is metastable below 825 K and is obtained only by rapid quenching from T > 825 K. The isotypic compounds crystallize in a new tetragonal tP28 structure type (P4/nnc). The characteristic unit is the hitherto unknown clustercation Bi₂⁴⁺, with the mean bond length d(Bi–Bi) = 314.2 pm, the Raman frequency 102 cm^–1 ≤ ν_s ≤ 108 cm^–1, and the mean force constant of f = 0.68 N · cm^–1. The Electron Localization Function, ELF, shows the covalent Bi–Bi bond, the lone electron pairs of the ψ-octahedrally coordinated Bi(II) cations, and the polar character of the Bi–X bonds.     

Crystal Structures,Bonding and Electronic Structures of MM′As,a Series of New Ternary Arsenides (M = Zr,Hf; M′ = Fe,Co, Ni)

All six new arsenides were prepared by arc-melting of preheated mixtures of the monoarsenides MAs with the 3d metals Fe, Co, and Ni, respectively. The isostructural title compounds all form the Co₂Si structure type, in contrast to the corresponding phosphides with ZrNiP occurring in the Ni₂In type. The anomalous expansions of the unit cells from ZrCoAs to ZrNiAs (V = 178.5(3) ų versus V = 182.5(1) ų) and from HfCoAs to HfNiAs (V = 175.03(5) ų versus V = 177.0(1) ų) can be understood based on Extended Hückel calculations of the electronic structure of HfCoAs.     

Tantalcluster in oxidischer Matrix – Synthese und Strukturen der gemischtvalenten Oxotantalate M2–δTa15O32 (M = K,Rb (δ = 0); M = Sr (δ = 0.15), Ba (δ = 0.12))

Tantalum Cluster in an Oxidic Matrix – Synthesis and Structures of Mixed-Valence Oxotantalates M_2–δTa₁₅O₃₂ (M = K, Rb (δ = 0); M = Sr (δ = 0.15), Ba (δ = 0.12)) The mixed-valent oxides Sr_1.85Ta₁₅O₃₂ ( 1 ), Ba_1.88Ta₁₅O₃₂ ( 2 ), K₂Ta₁₅O₃₂ ( 3 ), Rb₂Ta₁₅O₃₂ ( 4 ) were prepared from appropriate mixtures of Ta₂O₅, tantalum and the corresponding carbonate at 1520–1670 K in sealed tantalum tubes. According to X-ray single crystal structure analyses the oxides crystallize in the space group R3¯, Z = 1. The lattice parameters in the hexagonal setting are a = 777.36(11), c = 3516.2(7) pm for 1 , a = 778.87(11), c = 3548.1(7) pm for 2 , a = 780.7(2), c = 3573.1(11) pm for 3 , and a = 781.90(11), c = 3593.0(7) pm for 4 . The oxide ions form a defect dense packing with the layer sequence chhhh. Anti-cuboctahedral sites are completely occupied by the alkali metal cations. The alkaline earth cations occupy 92 to 94% of such sites; they are displaced from the centres. Smaller voids are located in the centres of the cuboctahedral Ta₆O₁₂ clusters forming the characteristic structural unit of these low-valent oxotantalates. In case of 3 and 4 the clusters have 13 electrons, in case of 1 and 2 they have close to 15 electrons available for Ta–Ta-bonding. Moreover, the structures of the alkali and alkaline earth metal compounds differ notably with respect to the spectrum of Ta–O and Ta–Ta distances in the Ta₃O₁₃ octahedra triples forming another characteristic structural unit for these oxides. Such differences are traced back to distinct local charge balances for the uni- and divalent cations. The oxides 2 , 3 are semiconductors with band gaps ranging from 130 to 360 meV.     

Synthese,Kristallstrukturen und thermisches Verhalten von Er2(SO4)3 · 8 H2O und Er2(SO4)3 · 4 H2O

Syntheses, Crystal Structures, and Thermal Behavior of Er₂(SO₄)₃ · 8 H₂O and Er₂(SO₄)₃ · 4 H₂O Evaporation of aqueous solutions of Er₂(SO₄)₃ yields light pink single crystals of Er₂(SO₄)₃ · 8 H₂O. X-ray single crystal investigations show that the compound crystallizes monoclinically (C2/c, Z = 8, a = 1346.1(3), b = 667.21(1), c = 1816.2(6) pm, β = 101.90(3)°, R_all = 0.0169) with eightfold coordination of Er³⁺, according to Er(SO₄)₄(H₂O)₄. DSC- and temperature dependent X-ray powder investigations show that the decomposition of the hydrate follows a two step mechanism, firstly yielding Er₂(SO₄)₃ · 3 H₂O and finally Er₂(SO₄)₃. Attempts to synthesize Er₂(SO₄)₃ · 3 H₂O led to another hydrate, Er₂(SO₄)₃ · 4 H₂O. There are two crystallographically different Er³⁺ ions in the triclinic structure (P 1, Z = 2, a = 663.5(2), b = 905.5(2), c = 1046.5(2) pm, α = 93.59(3)°, β = 107.18(2)°, γ = 99.12(3)°, R_all = 0.0248). Er(1)³⁺ is coordinated by five SO₄^2– groups and three H₂O molecules, Er(2)³⁺ is surrounded by six SO₄^2– groups and one H₂O molecule. The thermal decomposition of the tetrahydrate yields Er₂(SO₄)₃ in a one step process. In both cases the dehydration produces the anhydrous sulfate in a modification different from the one known so far.     

Disupersilylsilanide M(SiHR*2)2 der Zinkgruppenmetalle (M = Zn,Cd, Hg; R* = SitBu3): Synthesen,Charakterisierung und Strukturen

Disupersilylsilanides M(SiHR^*₂)₂ of Metals of the Zinc Group (M = Zn, Cd, Hg; R* = Si t Bu₃): Syntheses, Characterization, and Structures Bis(disupersilyl)silylmetals M(SiHR )₂ (R* = Supersilyl = SitBu₃) with M = Zn, Cd, Hg are obtained in tetrahydrofuran/benzene/pentane by the reaction of NaSiHR with ZnCl₂, CdI₂, HgCl₂ in the molar ratio 2 : 1. The compounds form colorless, in organic media soluble, not hydrolysis‐ and air‐sensitive crystals, the stabilities of which for thermolysis or photolysis decrease in the row Zn > Hg > Cd compound. According to X‐ray structure analyses, the compounds M(SiHR )₂ are monomeric with a – to date not observed – non‐linear framework –M– (angle SiMSi for M(SiHR )₂ with M = Zn/Cd/Hg 170.7/174.2/174.4°).     

Synthesis and Structure of (NH4)2[(AuI4)(MI4)] (M = Ga,In)

The compounds (NH₄)₂[(AuI₄)(MI₄)] (M = Ga, In) were obtained in sealed glass ampoules by reaction of I₂, NH₄I, Au and Ga or In as air‐sensitive black crystals. Both compounds crystallize in the orthorhombic space group Pnma (No. 62) and are isotypic: (NH₄)₂[(AuI₄)(GaI₄)], a = 12.619(2), b = 20.625(5) and c = 7.693(2) Å; (NH₄)₂[(AuI₄)(InI₄)], a = 12.587(2), b = 20.606(5) and c = 7.696(2) Å. The structures can be described as constituted of NH₄⁺ cations and anionic zig zag chains of alternating tetrahedral MI₄^– (M = In, Ga) and square planar AuI₄^– units running along [010]. Within the chains, the MI₄^– ions form weak interactions with two of their I atoms to the AuI₄^– ions resulting in strongly elongated AuI₆ octahedra.     

Untersuchungen zur Darstellung von [CpxSb{M(CO)5}2] (Cpx = Cp,Cp*; M = Cr,W)

Investigations of the Synthesis of [Cp^xSb{M(CO)₅}₂] (Cp^x = Cp, Cp*; M = Cr, W) The reaction of CpSbCl₂ with [Na₂{Cr₂(CO)₁₀}] leads to the chlorostibinidene complex [ClSb{Cr(CO)₅}₂(thf)] ( 1 ), whereas the reaction of CpSbCl₂ with [Na₂{W₂(CO)₁₀}] results in the formation of the complexes [ClSb{W(CO)₅}₃] ( 2 ), [Na(thf)][Cl₂Sb{W(CO)₅}₂] ( 3 ), [ClSb{W(CO)₅}₂(thf)] ( 4 ) and [Sb₂{W(CO)₅}₃] ( 5 ). The stibinidene complex [CpSb{Cr(CO)₅}₂] ( 6 ) is obtained by the reaction of [ClSb{Cr(CO)₅}₂] with NaCp, while its Cp* analogue [Cp*Sb{Cr(CO)₅}₂] ( 7 ) is formed via the metathesis of Cp*SbCl₂ with [Na₂{Cr₂(CO)₁₀}]. The products 2 , 3 , 4 and 7 are additionally characterised by X‐ray structure analyses.     

Synthese und Kristallstruktur von Hydrogenselenaten zweiwertiger Metalle – M(HSeO4)2 (M = Mg,Mn, Zn) und M(HSeO4)2 · H2O (M = Mn,Cd)

Synthesis and Crystal Structure of Hydrogen Selenates of Divalent Metals – M(HSeO₄)₂ (M = Mg, Mn, Zn) and M(HSeO₄)₂ · H₂O (M = Mn, Cd) New hydrogen selenates M(HSeO₄)₂ (M = Mg, Mn, Zn) and M(HSeO₄)₂ · H₂O (M = Mn, Cd) have been synthesized using MSeO₄ (M = Mg, Mn, Zn, Cd) and 90% selenic acid as starting materials. The crystal structures have been determined by X-ray single crystal crystallography. The compounds M(HSeO₄)₂ (M = Mg, Zn) belong to the structure type of Mg(HSO₄)₂, whereas Mn(HSeO₄)₂ forms a new structure type. Both hydrogen selenate monohydrates are isotypic to Mg(HSO₄)₂ · H₂O. In all compounds the metal atoms are octahedrally coordinated by oxygen atoms of different HSeO₄-tetrahedra. In the HSeO₄-tetrahedra the Se–OH-distances (mean value 1.70 Å) are about 0.1 Å longer than Se–O-distances (mean value 1.62 Å). In the structure of M(HSeO₄)₂ (M = Mg, Zn) there are zigzag chains of hydrogen bonded HSeO₄-tetrahedra. The structure of Mn(HSeO₄)₂ is characterized by chains of HSeO₄-tetrahedra in form of screws. Hydrogen bonds from and to water molecules connect double layers of MO₆-octahedra and HSeO₄-tetrahedra in the structures of M(HSeO₄)₂ · H₂O.     

Ternary Rhodium Borides A3Rh5B2 (A = Mg,Sc) and Quaternary Derivatives A2MRh5B2. Preparation,Crystal Structure (M = Main Group and 3 d Elements), and Magnetism (M = Mn,Fe)

The new ternary rhodium borides Mg₃Rh₅B₂ and Sc₃Rh₅B₂ (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti₃Co₅B₂ type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A_3–xM_xRh₅B₂ with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A₂MRh₅B₂: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti₃Co₅B₂ type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below T_N = 130 K, while Sc/Fe behaves ferromagnetically below T_C = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious.     

Compounds with Cluster Cations together with Cluster Anions [(M6X12)(EtOH)6]2+ besides [(Mo6Cl8)Cl4X2]2– (M = Nb,Ta; X = Cl,Br) – Synthesis and Crystal Structures

Compounds consisting of both cluster cations and cluster anions of the composition [(M₆X₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₄X₂] · n EtOH · m Et₂O (M = Nb, Ta; X = Cl, Br) have been prepared by the reaction of (M₆X₁₂)X₂ · 6 EtOH with (Mo₆Cl₈)Cl₄. IR data are given for three compounds. The structures of [(Nb₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 3 EtOH · 3 Et₂O 1 and [(Ta₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 6 EtOH 2 have been solved in the triclinic space group P1 (No. 2). Crystal data: 1 , a = 10.641(2) Å, b = 13.947(2) Å, c = 15.460(3) Å, α = 65.71(2)°, β = 73.61(2)°, γ = 85.11(2)°, V = 2005.1(8) ų and Z = 1; 2 , a = 11.218(2) Å, b = 12.723(3) Å, c = 14.134(3) Å, α = 108.06(2)°, β = 101.13(2)°, γ = 91.18(2)°, V = 1874.8(7) ų and Z = 1. Both structures are built of octahedral [(M₆Cl₁₂)(EtOH)₆]²⁺ cluster cations and [(Mo₆Cl₈)Cl₆]^2– cluster anions, forming distorted CsCl structure types. The Nb–Nb and Ta–Ta bond lengths of 2.904 Å and 2.872 Å (mean values), respectively, are rather short, indicating weak M–O bonds. All O atoms of coordinated EtOH molecules are involved in H bridges. The Mo–Mo distances of 2.603 Å and 2.609 Å (on average) are characteristic for the [(Mo₆Cl₈)Cl₆]^2– anion, but there is a clear correlation between the number of hydrogen bridges to the terminal Cl and the corresponding Mo–Cl distances.     

Darstellung,Kristallstruktur und Eigenschaften von Ln3AuO6 (Ln = Sm,Eu, Gd)

Syntheses, Crystal Structures, and Properties of Ln₃AuO₆ (Ln = Sm, Eu, Gd) The title compounds have been prepared from amorphous Au₂O₃ · x H₂O (x = 1–3) and Ln₂O₃ (Ln = Nd, Sm, Eu) via solid state reaction under elevated oxygen pressure adding KOH as mineralizing agent. They crystallize in a new structure type (triclinic, P1, Z = 1, Sm₃AuO₆: a = 3.7272(2) Å, b = 5.6311(2) Å, c = 7.0734(3) Å, α = 90.32(2)°, β = 103.983(3)°, γ = 90.822(2)°, 125 powder intensities, R_p = 2.57%, Eu₃AuO₆: a = 3.7012(2) Å, b = 5.6134(2) Å, c = 7.0652(4) Å, α = 90.838(3)°, β = 102.956(3)°, γ = 90.909(2)°, 122 powder intensities, R_p = 3.16%, Gd₃AuO₆: a = 3.6720(2) Å, b = 5.5977(2) Å, c = 7.0636(2) Å, α = 90.509(2)°, β = 102.889(3)°, γ = 91.068(2)°, 3424 reflections, R₁ = 12.90%). The crystal structure was solved and refined from single crystal data of Gd₃AuO₆. The structures of Sm₃AuO₆ and Eu₃AuO₆ were refined from powder diffraction data. The isolated square planar AuO₄ units are stacked along the a‐axis and are linked by LnO₆‐ and LnO₆₊₁‐polyhedra. One of the oxygen atoms is exclusively coordinated by trivalent lanthanides, in tetrahedral geometry. The lanthanoid aurates decompose between 700 and 900 °C into Ln₂O₃, Au and O₂. The magnetic moments μ_eff(Gd₃AuO₆) = 7.9 μ_B and, at 20 °C respectively, μ_eff(Sm₃AuO₆) = 1.55 μ_B as well as μ_eff(Eu₃AuO₆) = 3.5 μ_B confirm that the lanthanides are trivalent. The UV/VIS absorption spectra can be interpreted at assuming free ions.