Synthese und Struktur der Nitridoborat‐Nitride Ln4(B2N4)N (Ln = La,Ce) des Formeltyps Ln3+x(B2N4)Nx (x = 0, 1, 2)

Synthesis and Structure of Nitridoborate Nitrides Ln₄(B₂N₄)N (Ln = La, Ce) of the Formula Type Ln_3+x(B₂N₄)N_x (x = 0, 1, 2) The missing member of the formula type Ln_3+x(B₂N₄)N_x with x = 1 was synthesized and characterized for Ln = La and Ce. According to the single‐crystal X‐ray structure solution Ce₄(B₂N₄)N crystallizes in the space group C2/m (Z = 2) with the lattice parameters a = 1238.2(1) pm, b = 357.32(3) pm, c = 905.21(7) pm and β = 129.700(1)°. The anisotropic structure refinement converged at R1 = 0.039 and wR2 = 0.099 for all independent reflections. A powder pattern of La₄(B₂N₄)N was indexed isotypically with a = 1260.4(1) pm, b = 366.15(3) pm, c = 919.8(1) pm and β = 129.727(6)°. A structure rational for nitridoborates and nitridoborate nitrides containing B₂N₄ ions with the general formula Ln_3+x(B₂N₄)N_x with x = 0, 1, 2 is presented.     

Über die Kristallstruktur der Phase La5B2C6

On the Crystal Structure of the Phase La₅B₂C₆ A homogeneous sample of La₅B₂C₆ annealed at 1000 °C was investigated by X‐ray powder and single‐crystal as well as electron diffraction. The crystal structure was refined in space group P4/ncc (a = 8.590(1) Å, b = 12.398(1) Å, Z = 4, ρ_calc = 5.723 g/cm, ρ_exp = 5.70 g/cm) allowing for anharmonic displacement parameters for the metal atoms. The structure contains twofold disordered CBCC units in bicapped tetragonal antiprismatic coordination in contrast to C₂ and CBC units in earlier investigations.     

Über Oxotantalate der Lanthanide des Formeltyps MTaO4 (M = La – Nd,Sm – Lu)

About Lanthanide Oxotantalates with the Formula MTaO₄ (M = La – Nd, Sm – Lu) Besides being a by‐product of solid state syntheses in tantalum ampoules the lanthanide(III) oxotantalates of the formula MTaO₄ can be easily prepared by sintering lanthanide sesquioxide M₂O₃ and tantalum(V) oxide Ta₂O₅ with sodium chloride as flux. Under these conditions two structure types emerge depending upon the M³⁺ cationic radius. For M = La – Pr the MTaO₄‐type tantalates crystallize in the space group P2₁/c with lattice constants of a = 762(±1), b = 553(±4), c = 777(±4) pm, β = 101(±1)° and four formula units per unit cell. With M = Nd, Sm – Lu, the monoclinic cell dimensions (space group P2/c) shrink to the lattice constants like a = 516(±9), b = 551(±9), c = 534(±9) pm, β = 96.5(±0.3)° and there are only two formula units present. Both structures show a coordination sphere of eight oxygen atoms for the lanthanide trications shaped as distorted square antiprism for the structure with the larger lanthanides (in the following referred to as A‐type) and as trigonal dodecahedron for the structure with the smaller ones (called as B‐type in the following). The coordination environment about the Ta⁵⁺ cations can be described as a slightly distorted octahedron (CN = 6) for the A‐type structure of MTaO₄ and a heavily distorted one (CN = 6) for the B‐type. The difference between the two types results from the interconnection of these [TaO₆]^7? octahedra. Whereas they are connected via four vertices to form corrugated layers according to parallel the bc‐plane in the A‐type, the octahedra of the B‐type MTaO₄ structure share edges to built up zig‐zag chains along the c axis.     

X‐Ray Single Crystal Refinement and Superconductivity of La3Ni2B2N3

Crystalline samples of La₃Ni₂B₂N₃ were synthesized using solid state metathesis reactions from combinations of La, LaCl₃, NiCl₂ together with Li₃BN₂. The structure was determined by single crystal X‐ray diffraction (I4/mmm (No. 139), a = 372.95(2) pm, c = 2056.3(2) pm, R₁ = 0.027, wR₂ = 0.062) and confirmed earlier results from neutron powder diffraction. La₃Ni₂B₂N₃ contains BN units capping square planar Ni layers. Isolated nitrogen atoms reside in La₆ octahedra. Magnetic measurements on several bulk samples exhibit superconductivity at temperatures below 14.6 K.     

Zur Kenntnis von Tripraseodym‐hexanitridotriborat Pr3B3N6: Neue Synthese und Verfeinerung der Kristallstruktur

On Tripraseodymium Hexanitridotriborate Pr₃B₃N₆: New Synthesis and Crystal Structure Refinement Single‐crystalline Pr₃B₃N₆ was obtained by the reaction of praseodymium and BN_x(NH)_y(NH₂)_z in a NaCl melt under N₂ atmosphere in a high‐frequency furnace at 1250 °C. Contrary to literature data, Pr₃B₃N₆ crystallizes in the centrosymmetric space group R 3 c as revealed by single‐crystal X‐ray diffraction (a = 1211.95(9), c = 701.53(7) pm, Z = 6, R1 = 0.0258, wR2 = 0.0658). In the solid, Pr₃B₃N₆ contains Pr³⁺ and planar cyclotrinitridoborate units B₃N₆^9–. The anions represent motifs from the structure of hexagonal boron nitride (h‐BN) and they are stacked analogously along [001]. Both the bond lengths B–N (average value 147.8 pm) and the interionic distances between the anions (350.8 pm) are comparable with the values in h‐BN.     

Das Chloridnitrat PrCl2(NO3) · 5 H2O mit kationischen und anionischen Komplexen gemäß [PrCl2(H2O)6][PrCl2(NO3)2(H2O)4]

The Chloride Nitrate PrCl₂(NO₃) · 5 H₂O with Cationic and Anionic Complexes according to [PrCl₂(H₂O)₆][PrCl₂(NO₃)₂(H₂O)₄] Green single crystals of PrCl₂(NO₃) · 5 H₂O have been obtained from an aqueous solution of PrCl₃ and Pr(NO₃)₃. The crystal structure [monoclinic, P2/c, Z = 4, a = 1228.8(3), b = 648.4(1), c = 1266.0(4) pm, β = 91.91(3)°] contains cationic and anionic Pr³⁺ complexes according to [PrCl₂(H₂O)₆][PrCl₂(NO₃)₂(H₂O)₄]. Both nitrate groups of the anionic complex act as bidentate chelating ligands. Hydrogen bonds are observed with water molecules as donors and chlorine as well as oxygen atoms as acceptors.     

CoSm(SeO3)2Cl,CuGd(SeO3)2Cl,MnSm(SeO3)2Cl,CuGd2(SeO3)4 und CuSm2(SeO3)4: Übergangsmetallhaltige Selenite von Samarium und Gadolinum

CoSm(SeO₃)₂Cl, CuGd(SeO₃)₂Cl, MnSm(SeO₃)₂Cl, CuGd₂(SeO₃)₄ and CuSm₂(SeO₃)₄: Transition Metal containing Selenites of Samarium and Gadolinum The reaction of CoCl₂, Sm₂O₃, and SeO₂ in evacuated silica ampoules lead to blue single crystals of CoSm(SeO₃)₂Cl (triclinic, , Z = 4, a = 712.3(1), b = 889.5(2), c = 1216.2(2) pm, α = 72.25(1)°, β = 71.27(1)°, γ = 72.08(1)°, R_all = 0.0586). If MnCl₂ is used in the reaction light pink single crystals of MnSm(SeO₃)₂Cl (triclinic, , Z = 2, a = 700.8(2), b = 724.1(2), c = 803.4(2) pm, α = 86.90(3)°, β = 71.57(3)°, γ = 64.33(3)°, R_all = 0.0875) are obtained. Green single crystals of CuGd₂(SeO₃)₂Cl (triclinic, , Z = 4, a = 704.3(4), b = 909.6(4), c = 1201.0(7) pm, α = 70.84(4)°, β = 73.01(4)°, γ = 70.69(4)°, R_all = 0.0450) form analogously in the reaction of CuCl₂ and Gd₂O₃ with SeO₂. CoSm(SeO₃)₂Cl contains [CoO₄Cl₂] octahedra, which are connected via one edge and one vertex to infinite chains. The Mn²⁺ ions in MnSm(SeO₃)₂Cl are also octahedrally coordinated by four oxygen and two chlorine ligands. The linkage of the polyhedra to chains occurs exclusively via edges. Both, the cobalt and the manganese compound show the Sm³⁺ ions in eight and ninefold coordination of oxygen atoms and chloride ions. In CuGd(SeO₃)₂Cl the Cu²⁺ ions are coordinated by three oxygen atoms and one Cl^— ion in a distorted square planar manner. One further Cl^— and one further oxygen ligand complete the [CuO₃Cl] units yielding significantly elongated octahedra. The latter are again connected to chains via two common edges. For the Gd³⁺ ions coordination numbers of ?8 + 1”? and nine were found. Single crystals of the deep blue selenites CuM₂(SeO₃)₄ (M = Sm/Gd, monoclinic, P2₁/c, a = 1050.4(3)/1051.0(2), b = 696.6(2)/693.5(1), c = 822.5(2)/818.5(2) pm, β = 110.48(2)°/110.53(2)°, R_all = 0.0341/0.0531) can be obtained from reactions of the oxides Sm₂O₃ and Gd₂O₃, respectively, with CuO and SeO₂. The crystal structure contains square planar [CuO₄] groups and irregular [MO₉] polyhedra.     

Synthese und Kristallstrukturen von (3‐Methylpyridinium)3[DyCl6] und (3‐Methylpyridinium)2[DyCl5(Ethanol)]

Preparation and Structure of (3‐Methylpyridinium)₃[DyCl₆] and (3‐Methylpyridinium)₂[DyCl₅(Ethanol)] The complex chlorides (3‐Methylpyridinium)₃[DyCl₆] ( 1 ) and (3‐Methylpyridinium)₂[DyCl₅(Ethanol)] ( 2 ) have been prepared for the first time. The crystal structures have been determined from single crystal X‐ray diffraction data. 1 crystallizes in the trigonal space group R3c (Z = 36) with a = 2953.3(3) pm, b = 2953.3(3) pm and c = 3252.5(4) pm, compound 2 crystallizes in the triclinic space group P1 (Z = 2) with a = 704.03(8) pm, b = 808.10(8) pm, c = 1937.0(2) pm, α = 77.94(1)°, β = 87.54(1)° and γ = 83.26(1)°. The structures contain isolated octahedral building units [DyCl₆]^3– and [DyCl₅(Ethanol)]^2–, respectively.     

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.     

Synthese und Kristallstrukturen von (2‐Methylpyridinium)3[TbCl6] und (2‐Methylpyridinium)2[TbCl5(1‐Butanol)]

Preparation and Structure of (2‐Methylpyridinium)₃[TbCl₆] and (2‐Methylpyridinium)₂[TbCl₅(1‐Butanol)] The complex chlorides (2‐Methylpyridinium)₃[TbCl₆] (1) and (2‐Methylpyridinium)₂[TbCl₅(1‐Butanol)] (2) have been prepared for the first time. The crystal structures have been determinated from single crystal X‐ray diffraction data. 1 crystallizes in the monoclinic space group C2/c (Z = 8) with a = 3241,2(5) pm, b = 897,41(9) pm, c = 1774,2(2) pm and β = 97,83(2)°, 2 in the monoclinic space group P2₁/n (Z = 4) with a = 1372,96(16) pm, b = 997,57(9) pm, c = 1820,5(2) pm and β = 108,75(1)°. The structures contain isolated octahedral building units [TbCl₆]^3– and [TbCl₅(1‐Butanol)]^2–, respectively.     

NC12H8(NH)2[Gd(N3C12H8)4] und [Gd(N3C12H8)3(N3C12H9)]·PhCN: Ein Beitrag zur Reaktivität und Kristallchemie homoleptischer Selten‐Erd‐Pyridylbenzimidazolate

NC₁₂H₈(NH)₂[Gd(N₃C₁₂H₈)₄] and [Gd(N₃C₁₂H₈)₃(N₃C₁₂H₉)]·PhCN: A Contribution to the Reactivity and Crystal Chemistry of Homoleptic Pyridylbenzimidazolates of the Rare Earth Elements Transparent colourless crystals of the compound NC₁₂H₈(NH)₂[Gd(N₃C₁₂H₈)₄] were obtained by solvent‐free reaction of gadolinium metal with molten 2‐(2‐Pyridyl)‐benzimidazole. Transparent yellow crystals of the compound [Gd(N₃C₁₂H₈)₃(N₃C₁₂H₉)]·PhCN were obtained by further reacting NC₁₂H₈(NH)₂[Gd(N₃C₁₂H₈)₄] with benzonitrile thermally. Both compounds exhibit homoleptic pure nitrogen coordinations of gadolinium, the PhCN ligand is not coordinating. Whilst NC₁₂H₈(NH)₂[Gd(N₃C₁₂H₈)₄] is salt like and consists of (NC₁₂H₈(NH)₂)⁺ and [Gd(N₃C₁₂H₈)₄]^— ions, [Gd(N₃C₁₂H₈)₃(N₃C₁₂H₉)]·PhCN has a molecular structure of uncharged [Gd(N₃C₁₂H₈)₃(N₃C₁₂H₉)] units.     

Tieftemperatur‐Oxidation in flüssigem Ammoniak: [Eu2(Ind)4(NH3)6], das erste Indolat eines Selten‐Erd‐Elementes

Low‐Temperature Oxidation in Liquid Ammonia: [Eu₂(Ind)₄(NH₃)₆], the First Indolate of a Rare Earth Element Intensively yellow to orange coloured, transparent crystals of [Eu₂(Ind)₄(NH₃)₆] were obtained by low‐temperature oxidation of europium metal with indole (C₈H₆NH) in liquid ammonia at —50 °C and subsequent melting of the reaction mixture in excess indole at 120 °C. [Eu₂(Ind)₄(NH₃)₆] has a dimeric structure and contains divalent Eu. The coordination sphere around the europium atoms consists of five N atoms of two cisoid indolate anions and three NH₃ molecules as well as an η⁵‐coordinating π‐system of another indolate ligand, bridging to the next Eu atom with an sp²‐orbital.     

Nd4N2Se3 und Tb4N2Se3: Zwei nicht‐isotype Lanthanoid(III)‐Nitridselenide

Nd₄N₂Se₃ and Tb₄N₂Se₃: Two non‐isotypical Lanthanide(III) Nitride Selenides The non‐isotypical nitride selenides M₄N₂Se₃ of neodymium (Nd₄N₂Se₃) and terbium (Tb₄N₂Se₃) are formed by the reaction of the respective rare‐earth metal with sodium azide (NaN₃), selenium and the corresponding rare‐earth tribromide (MBr₃) at 900 °C in evacuated silica ampoules after seven days. Each of them crystallizes monoclinically in the space group C2/c with Z = 4 for Nd₄N₂Se₃ (a = 1300.47(4), b = 1009.90(3), c = 643.33(2) pm, β = 90.039(2)°) and in the space group C2/m with Z = 2 for Tb₄N₂Se₃ (a = 1333.56(5), b = 394.30(2), c = 1034.37(4) pm, β = 130.377(2)°), respectively. The crystal structures differ fundamentally in the linkage of the structure dominating N^3‐ centred (M³⁺)₄ tetrahedra. In Nd₄N₂Se₃, the [NNd₄] units are edge‐linked to bitetrahedra which are cross‐connected to [N(Nd1)(Nd2)]³⁺ layers via their remaining four corners, whereas the [NTb₄] tetrahedra in Tb₄N₂Se₃ share cis‐oriented edges to form strands [N(Tb1)(Tb2)]³⁺. Both structures contain two crystallographically different M³⁺ cations, that show coordination numbers of six and seven (Nd₄N₂Se₃) or twice six (Tb₄N₂Se₃), respectively, relative to the anions (N^3‐ und Se^2‐). Each of the two independent kinds of Se^2‐ anions provide the three‐dimensional linkage as well as the charge balance. The particular axial ratio a/c and the monoclinic reflex angle offer two choices for fixing the unit cell of Tb₄N₂Se₃.     

Two New Benzoate‐di(methylcyclopentadienyl)ytterbium(III) Complexes: [Yb(MeCp)2(O2CC6F5)]2 and [Yb(MeCp)2(O2C‐o‐HC6F4)]2

Transparent orange crystals of [Yb(MeCp)₂(O₂CC₆F₅)]₂ and [Yb(MeCp)₂(O₂C‐o‐HC₆F₄)]₂ were obtained by oxidation of Yb(MeCp)₂ with M(O₂CR) (M = ¹/₂ Hg, Tl; R = C₆F₅, o‐HC₆F₄) in tetrahydrofuran. They have a dimeric structure with bridging bidentate (O, O')‐benzoate groups and eight coordinated ytterbium. Both crystallise isotypic in the orthorhombic space group Pbca. Room temperature as well as low temperature single crystal X‐ray investigations show the o‐H/F positions in [Yb(MeCp)₂(O₂C‐o‐HC₆F₄)]₂ not to be ordered.     

Über den H‐ und A‐Typ von La2[Si2O7]

On the H‐ and A‐Type Structure of La₂[Si₂O₇] By thermal decomposition of La₃F₃[Si₃O₉] at 700 °C in a CsCl flux single crystals of a new form of La₂[Si₂O₇] have been found which is called H type (triclinic, P1; a = 681.13(4), b = 686.64(4), c = 1250.23(8) pm, α = 82.529(7), β = 88.027(6), γ = 88.959(6)°; V_m = 87.223(9) cm³/mol, D_x = 5.113(8) g/cm³, Z = 4) continuing Felsche's nomenclature. It crystallizes isotypically to the triclinic K₂[Cr₂O₇] in a structure closely related to that of A–La₂[Si₂O₇] (tetragonal, P4₁; a = 683.83(7), c = 2473.6(4) pm; V_m = 87.072(9) cm³/mol, D_x = 5.122(8) g/cm³, Z = 8). For comparison, the latter has been refined from single crystal data, too. Both the structures can be described as sequence of layers of each of two crystallographically different [Si₂O₇]^6– anions always built up of two corner‐linked [SiO4] tetrahedra in eclipsed conformation with non‐linear Si–O–Si bridges (∢(Si–O–Si) = 128–132°) piled up in [001] direction and aligned almost parallel to the c axis. They differ only in layer sequence: Whereas the double tetrahedra of the disilicate units are tilted alternating to the left and in view direction ([010]; stacking sequence: AB) in H–La₂[Si₂O₇], after layer B there follow due to the 4₁ screw axis layers with anions tilted to the right and tilted against view direction ([010]; stacking sequence: ABA′B′) in A–La₂[Si₂O₇]. The extremely irregular coordination polyhedra around each of the four crystallographically independent La³⁺ cations in both forms (H and A type) consist of eight to ten oxygen atoms in spacing intervals of 239 to 330 pm. The possibility of more or less ordered intermediate forms will be discussed.     

Über das Lithiumchloromolybdat Li[Mo6Cl13]

On the Lithium Chloromolybdate Li[Mo₆Cl₁₃] Li[Mo₆Cl₁₃] was obtained as single phase product from a solid state reaction of MoCl₅, Mo powder, and LiCl at 800 °C. The structure as refined by single crystal X‐ray diffraction, contains one‐dimensional [Mo₆Cl Cl Cl ]^– chains, formed by Cl^a–a bridges. Lithium ions are located in tunnels along the chain‐direction, each of them being surrounded by a distorted tetrahedral arrangement of outer chlorine ligands (Cl^a) belonging to four different clusters.     

Synthese von Cadmiumnitrid Cd3N2 durch thermischen Abbau von Cadmiumazid Cd(N3)2 und Kristallstrukturbestimmung aus Röntgen‐Pulverbeugungsdaten

Synthesis of Cadmium Nitride Cd₃N₂ by Thermolysis of Cadmium Azide Cd(N₃)₂ and Crystal Structure Determination from X‐ray Powder Diffraction Data Cadmium nitride Cd₃N₂ was obtained by thermolysis of cadmium azide Cd(N₃)₂ at 2·10^?6 mbar and 210 °C. It was obtained as a black, crystalline powder which becomes brown in air due to formation of cadmium amide Cd(NH₂)₂. The crystal structure of Cd₃N₂ was determined from X‐ray powder diffraction data and refined by the Rietveld method ( , a = 10.829(9) Å, V = 1270(3) ų, Z = 16, R(F²) = 0.1196). Cd₃N₂ crystallizes in the anti‐bixbyite structure type and is isotypic to Ca₃N₂.     

Synthese und Kristallstrukturen neuer komplexer Chloride der Lanthanide mit 3, 5‐Dimethylpyridiniumkationen: (3, 5‐Dimethylpyridinium)2[LnCl4(H2O)2]Cl (Ln = La,Pr) und (3, 5‐Dimethylpyridinium)3[TbCl6]

Preparation and Crystal Structures of New Complex Clorides of Lanthanides containing 3, 5‐Dimethylpyridinium Cations: (3, 5‐Dimethylpyridinium)₂[LnCl₄(H₂O)₂]Cl (Ln = La, Pr) and (3, 5‐Dimethylpyridinium)₃[TbCl₆] Crystals of the complex chlorides (3, 5‐dimethylpyridinium)₂[LaCl₄(H₂O)₂]Cl ( 1 ), (3, 5‐dimethylpyridinium)₂[PrCl₄(H₂O)₂]Cl ( 2 ) and (3, 5‐dimethylpyridinium)₃[TbCl₆] ( 3 ) have been prepared by reaction of LnCl₃ · x H₂O (Ln = La, Pr, Tb; x = 6‐7) with 3, 5‐dimethylpyridiniumchloride in ethanol/butanol solution. The crystal structures have been determined from single crystal X‐ray diffraction data. The compounds 1 and 2 are isotypic with each other and crystallize in the triclinic space group P1¯ (Z = 2). The 3, 5‐dimethylpyridinium cations are linked by hydrogen bonds to the anionic part of the structure built up by isolated chloride ions and strings of edge coupled triangulated dodecahedra [LnCl_4/2Cl₂(H₂O)₂]^—. The organic units are arranged forming a “π‐stacking”. 3 cristallizes monoclinically in the space group P2₁/c (Z = 4). The structure contains octahedral building units [TbCl₆]^3—. These octahedra are interconnected by the organic cations via hydrogen bonds forming chains parallel to [0 0 1].     

Quaternäre Caesium‐Kupfer(I)‐Lanthanoid(III)‐Selenide vom Typ CsCu3M2Se5 (M = Sm,Gd — Lu)

Quaternary Cesium Copper(I) Lanthanoid(III) Selenides of the Type CsCu₃M₂Se₅ (M = Sm, Gd — Lu) By oxidation of mixtures of copper and lanthanoid metal with elemental selenium in molar ratios of 1 : 1 : 2 and in addition of CsCl quaternary cesium copper(I) lanthanoid(III) selenides with the formula CsCu₃M₂Se₅ (M = Sm, Gd — Lu) were obtained at 750 °C within a week from torch‐sealed evacuated silica tubes. An excess of CsCl as flux helps to crystallize golden yellow or red, needle‐shaped, water‐resistant single crystals. The crystal structure of CsCu₃M₂Se₅ (M = Sm, Gd — Lu) (orthorhombic, Cmcm, Z = 4; e. g. CsCu₃Sm₂Se₅: a = 417.84(3), b = 1470.91(8), c = 1764.78(9) pm and CsCu₃Lu₂Se₅: a = 407.63(3), b = 1464.86(8), c = 1707.21(9) pm, respectively) contains [MSe₆]^9— octahedra which share edges to form double chains running along [100]. Those are further connected by vertices to generate a two‐dimensional layer parallel to (010). By edge‐ and vertex‐linking of [CuSe₄]^7— tetrahedra two crystallographically different Cu⁺ cations build up two‐dimensional puckered layers parallel to (010) as well. These sheet‐like structure interconnects the equation/tex2gif-stack-3.gif{[M₂Se₅]^4—} layers to create a three‐dimensional network according to equation/tex2gif-stack-4.gif{[Cu₃M₂Se₅]^—}. Thus empty channels along [100] form, apt to take up the Cs⁺ cations. These are surrounded by eight plus one Se^2— anions in the shape of (2+1)‐fold capped trigonal prisms with Cs—Se distances between 348 and 368 pm (8×) and 437 (for M = Sm) or 440 pm (for M = Lu), respectively, for the ninth ligand.     

Crystal Structure of two Lanthanide(III) Glycolate Complexes, [Lu(HOCH2COO)2(H2O)4][Lu(HOCH2COO)4] and Dy2(OCH2COO)2(HOCH2COO)2 · 4H2O. An X‐Ray Diffraction and Vibrational Spectroscopic Study

The crystal structure of [Lu(HOCH₂COO)₂(H₂O)₄][Lu(HOCH₂COO)₄] ( 1 ) and Dy₂(OCH₂COO)₂(HOCH₂COO)₂ · 4H₂O ( 2) were determined by X‐ray crystallography. The space group of 1 and 2 are P2/c and P2₁/c, respectively. In 1 , discrete anions and cations held together by hydrogen bonds form the lattice, while the structure of 2 is a 3‐D network of cross‐linked metal‐ligand chains. The lanthanides are eight‐coordinated by chelating glycolate ligands and water molecules with distorted dodecahedral coordination. The core of 2 is a centrosymmetric dimer complex formed by two dysprosium atoms bridged by two oxygen atoms from deprotonated hydroxyl groups of glycolate ligands. The vibration spectra of the crystals were also measured and compared to each other.