Neuartige Polyanionen in Zintlphasen Zur Kenntnis von Na7Al2Sb5

New Types of Polyanions in Zintl Phases: On Na₇Al₂Sb₅ The new compound Na₇Al₂Sb₅ crystallizes in the monoclinic system, space group P2₁/m (Nr. 11) with the lattice constants AlSb₄-tetrahedra are connected by common corners, edges and Sb₂ groups to anionic sheets, between which the Na⁺ ions are located.     

Zur Kenntnis von Sr2CrMnO6

About the New Compound Sr₂CrMnO₆ Sr₂CrMnO₆ was prepared and investigated by X-ray single crystal data (a = 541.6; c = 664.0 pm; space group C–P3 ). The structure is related to the distorted perovskites, the differences to SrCrO₃ and SrMnO₃ are discussed.     

Zur Kenntnis von Sr2Bi3V3O14

On Sr₂Bi₃V₃O₁₄ Single crystals of the hitherto unknown compound Sr₃Bi₃V₃O₁₄ were prepared and investigated by X-ray work. It crystallizes with triclinic symmetry, space group P1 , a = 7.0838, b = 7.1732, c = 14.1067 Å; α = 97.46, β = 98.70, γ = 110.99°, Z = 2. The crystal structure is characterized by VO₄ tetrahedra and one side open Bi³⁺ coordination inside Bi₂O₁₁ groups.     

Zur Kenntnis von Sr2CuO2Br

Inhaltsübersicht. Sr₂CuO₂Br wurde in geschlossenen Cu-Bömbchen dargestellt und an Einkristallen röntgenographisch untersucht (a = 4,0235; c = 28,5103 A; Raumgruppe D⁵_2d–R$3m). Sr²⁺ besitzt oktaedrische Koordinationspolyeder aus je drei Br^– und O^2–. Die Oktaeder sind in Doppelschichten angeordnet und werden von hantelförmig koordinierten Cu⁺-Ionen längs [001] verknüpft. About Sr₂CuO₂Br Single crystal of the unknown compound Sr₂CuO₂Br were prepared in closed Cu-tubes and examined by single X-ray diffractometer investigation (a = 4.0235; c = 28.5109 A; space group D⁵_3d–R$3m). Sr²⁺ has octahedral coordination of 3 Br^– and 3 O^2–. Cu⁺ shows a dumb-bell-like O^2– surrounding.     

Über Erdalkalimetall-Oxocuprate. V. Zur Kenntnis von Ca2CuO3 und SrCuO2

The hitherto unknown compounds Ca₂CuO₃ and SrCuO₂ were prepared and the structure determined by investigations of single crystal X-ray data. Results see ?Inhaltsübersicht”?.     

Zur Kenntnis von Ca3IrCuO6

On Ca₃IrCuO₆ Single crystals of Ca₃IrCuO₆ were prepared by a flux technique and investigated by single crystal X-ray work. It crystallizes with monoclinic symmetry, space group C—C12/c1; a = 9.032, b = 9.295, c = 6.466 Å, β = 91.35°, Z = 4. Ca₃IrCuO₆ is isotypic to Sr₃IrCuO₆. The square planare CuO₄ polygones show probably a slightly deficit accompanied by an adequate part of iridium in the oxydation state Ir⁵⁺.     

Zur Kenntnis von BaTiVO4 und SrTiVO4

On BaTiVO₄ and SrTiVO₄ BaTiVO₄ and SrTiVO₄ were prepared in closed systems by solid state reactions. They crystallize with orthorhombic symmetry (BaTiVO₄: space group D-Pmnb; a = 5.889; b = 7.889; c ?10.397 Å; Z = 4; SrTiVO₄: space group D-P2¹,2¹,2¹,2¹; a = 5.855; b = 7.572; c = 10.012 Å; Z = 4) and belong to β-K₂SO₄-type. The ordered occupation of point positions by Ba²⁺ and Tl⁺ as well as the decrease in symmetry of SrTiVO₄ are discussed.     

Zur Kenntnis der Struktur von Sr3(BN2)2

On the Structure of Sr₃(BN₂)₂ The structure of Sr₃(BN₂)₂ was determined on single-crystal X-ray data collected with a four-circle diffractometer. Sr₃(BN₂)₂ crystallizes in the cubic space group Im3 m (no. 229) with a = 764.56(3) pm and Z = 3. The structure contains linear BN^3?₂ ions with a B? N bond length of 135.8(6) pm. The straight forward synthesis employing metal nitrides plus boron nitride yielded crystalline powders of M₃(BN₂)₂ (M = Ca, Sr) at 1100°C (5 days). Cubic indexing of guinier patterns gave a = 765.8(1) pm for M = Sr and a = 734.7(2) pm for M = Ca. The structure refinement on a single crystal of Sr₃(BN₂)₂ revealed that one strontium site (2a; 0, 0, 0) is occupied by only about 50%. It has been tried to fully occupy this site with an alkali metal (A) to obtain ASr₄(BN₂)₃ (Z = 2). Reactions with A = Na yielded crystalline powders. Cubic indexing of the guinier pattern analogous to that of Sr₃(BN₂)₂ gave a = 754.2(1) pm.     

Zur Kenntnis der inversen Perowskite M3TO (M = Ca,Sr, Yb; T = Si,Ge, Sn,Pb)

On the Inverse Perovskites M₃TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb) Ca₃SiO and seven further inverse perovskites M₃TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb) were prepared in iron crucibles under argon by the reactions 6 M + TO₂ + T = 2 M₃TO, and 3 M+ TO = M₃TO for Yb₃PbO, respectively, at temperatures between 1123 to 1173 K. The crystal structures of all compounds were solved and refined using X—ray powder diffraction methods. Ca₃SiO, Ca₃GeO, Sr₃SiO, Sr₃GeO, Yb₃SiO and Yb₃GeO are orthorhombic perovskites (anti—GdFeO₃—type, space group Pbnm, No. 62, Z = 4). They show slightly distorted corner—sharing OM₆ octahedra that are tilted with respect to their positions in the ideal perovskite structure. The effective radii of the T^4— vary significantly with M²⁺. Thus, these perovskites can no longer be discussed in terms of the hard—sphere model, and Goldschmidt's tolerance factor does not apply. The ideal cubic representatives Yb₃SnO and Yb₃PbO were refined in space group Pm3¯m (anti—SrTiO₃ type, Z = 1).     

Zur Kenntnis von Ba2As6O11

Concerning Ba₂As₆O₁₁ Ba₂As₆O₁₁ was prepared by hydrothermal reaction of BaO with As₂O₃ at a temperature of 200°C. An X-ray structural analysis demonstrated that the phase contains highly condensed polyarsenate(III) anions (As₆O₁₁^4?)_n. A zweier double chain structure was observed for the anion, in which the individual chains are bridged to one another by two Ψ-AsO₃ tetrahedra, so that As₁₀O₁₀ rings are formed. The double chains are linked into “double sheets”, perpendicular to the b-axis, through relatively strong secondary O … As bonds with an average length of 2.68 Å.     

Zur Kenntnis von Cr2H2(As2O7)(As4O12)

The crystal structure of Cr₂H₂(As₂O₇)(As₄O₁₂) has been determined by X-ray methods using single crystal diffractometer data (1,152 reflections,R=0.054, orthorhombic,Pmmn,a=1317.7 (7),b=1124.9 (6),c=494.3 (4) pm,Z=2). The crystal structure contains both diarsenate(V) and the hitherto unknown cyclo-tetraarsenate(V)-anions. The magnetic susceptibility follows theCurie-Weiss law (=3.86±0.01 _B/Cr³⁺, =–31 K).

     

Über Oxobismutate. Zur Kenntnis von Na3BiO4 und Na3SbO4

On oxobismuthates. The compounds Na₃BiO₄ and Na₂SbO₄ Na₃BiO₄ crystallizes monoclinic in C⁴_2h; a = 5.87₁ b = 6.69⁶, c = 5.65₀ Å and β = 109,8° with Z = 2. We have a variant of the NaCl type, forming chains ¹_∞[BiO_4/2+2/1] along [001]. The MADELUNG part of lattice energy (MAPLE) of Na₃BiO₄ and different other structure models are calculated und discussed. Na₃SbO₄[a = 5.79₅, b = 6.59₅, c = 5.41₈ Å, β = 109.4°] is isotypic with Na₃BiO₄.     

Metastabile Oxometallate der Lanthanoidmetalle:.Zur Kenntnis von Sr3Pr4O9 und Sr3La2Sm2O9 mit einem Beitrag über SrPr2O4

Metastable Compounds of Rare Earth Oxides. About Sr₃Pr₄O₉ and Sr₃La₂Sm₂O₉ with a Remark about SrPr₂O₄ Sr₃Pr₄O₉ (A) and Sr₃La₂Sm₂O₉ (B) are for the first time prepared and investigated by X-ray single crystal work. Both compounds crystallize with monoclinic symmetry (space group C_s⁴? Cc, Z = 4) with (A) a = 11.468; b = 7.262; c = 13.218 Å; β = 115.61°, (B) a = 11.518; b = 7.263; c = 13.290 Å; β = 115.61°. (A) and (B) are metastable with high disorder in the metal positions. All of the metal positions are occupied with a statistical distribution of Sr²⁺ and Ln³⁺. (A) decomposes in the hitherto unknown compound SrPr₂O₄. It belongs to the calciumferrite type compounds.     

Zur Verbindungsbildung MO: M2O3. Zur Kenntnis von BaCr2O4

About a Compound Formation MO:M₂O₃. X. On BaCr₂O₄ For the first time single crystals of BaCr₂O₄ were prepared as a high temperature compound of the SrCr₂O₄-type. It crystallizes with orthorhomibic symmetry, space group D—Pmmn, a = 12,286; b = 5,921; c = 5,146 Å Z = 4. The crystal structure are described and the relationship to the metastable compounds α-CaCr₂O₄ and SrCr₂O₄ are discussed.     

Über Oxocuprate. XVII. Zur Kenntnis von Ca2CuO2Cl2 und Ca2CuO2Br2

About Oxocuprates. XVII. Ca₂CuO₂Cl₂ and Ca₂CuO₂Br₂ The so far unkown compounds Ca₂CuO₂Cl₂ (I) and Ca₂CuO₂Br₂ (II) were prepared and examined by X-ray single crystal methods. They are isotypic with Sr₂CuO₂Cl₂ ((I) a = 386.6, c = 1 497.5; (II) a = 387.5, c = 1 726.4 pm, space group d–I4/mmm). A discussion of the distances in respect to the structure shows that the stretching of octahedron around Cu²⁺ is no evidence for a Jahn-Teller-effect.     

Zur Kenntnis von K2GeO3

On K₂GeO₃ Single crystals of K₂GeO₃ have been prepared by heating K₂O and GeO₂ (K:Ge = 3.0:1.0; Ag-cylinder, 10 d, 700–800°C). The structure has been refined. K₂GeO₃: a = 2302.5(3), b = 3286.3(5), c = 545.2(1) pm; Pbca; R = 13.83%; R_w = 9.60% (different parameters see text). The structure of K₂GeO₃ will be discussed. The Effective Coordination Numbers, ECoN, the Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattic Energy, MAPLE, are calculated.     

Zur Kenntnis von Sr2RhF7. (Mit einer Bemerkung zur Kristallstruktur von RhF3)

On the Knowledge of Sr₂RhF₇ (With a Note of the Crystal structure of RhF₃) New prepared are dark redbrown single crystals of Sr₂RhF₇, monoclinic (P2₁/c) with a = 551.0(1), b = 1162.8(1), c = 864.0 (1) pm and β = 90.98(1), Z = 4 (4-circle diffraktometer, AgKα, ω-scan, 2228 I₀(hkl), R = 9.5 and R_w = 6.0%) and of RhF₃, trigonal, isotypic to VF₃(R3 c) with a = 487.3(1), c = 1355.0(1) pm, c/a = 2.781, Z = 6 (PW 1100, AgKα-, ω/2Θ-scan, 131 I₀(hkl), R = 4.0 and R_w = 3.3%). Sr₂RhF₇ crystallizes isotypic to Pb₂RhF₇ [2] with coordinationnumber 6 for Fh³⁺, not to Sr₂InF₇ [3] (CN 7 by In³⁺). Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, are calculated and compared with date of other Fluororhodates (III).     

Zur Kenntnis von K4PbO4 und Rb4PbO4

On K₄PbO₄ and Rb₄PbO₄ For the first time single crystals of K₄[PbO₄] have been prepared by heating K₄PbO₃ in O₂. The structure has been refined [K₄[PbO₄]: 3029 I₀(hkl), four circle diffractometer PW 1100, ω-scan, MoKα, R = 6.73%, R_w = 6.64%, P1 ; a = 658.62(15), b = 658.41(12), c = 986.64(21) pm, α = 79.74(2)°, β = 108.45(2)°, γ = 112.49(2)°, d_x = 3.79 g · cm^?3, d_pyk = 3.78 g · cm^?3, Z = 2; Rb₄[PbO₄]: a = 686.94(18), b = 684.43(18), c = 1020.73(21) pm, α = 79.28(2)°, β = 108.40(2)°, γ = 113.02(2)°, d_x = 4.87 g · cm^?3, d_pyk = 4.85 g · cm^?3, Z = 2, (from Rb₂PbO₃ and Rb₂O)]. Both compounds are isotypic with K₄SnO₄. The Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.