Zur Kenntnis eines gemischtvalenten Oxochromats(III,IV): Sr4Cr3O9

About a Mixed-Valence-Oxochromate(III, IV): Sr₄Cr₃O₉ Single crystals of the hitherto unknown compound Sr₄Cr₃O₉ were prepared and examined by four circle diffractometer technique (space group C–P3, a = 9.6182; c = 7.8736 Å, Z = 3). The point positions of chromium are occupied statistically by Cr³⁺ and Cr⁴⁺. The Cr³⁺/Cr⁴⁺-coordination is partly unusual, there are one dimensional chains of CrO₆-polyhedra incorporated in a [Sr₄O₉]^10?-network.     

Über Erdalkalioxoargentate. I. Strontiumargentat SrAg6O4

On Alkaline Earth Oxoargentates. I. Strontiumargentate SrAg₆O₄ Single crystals of SrAg₆O₄ were prepared at 400–500°C and 4000 atm. O₂-pressure. The X-ray investigation of the single crystals shows the orthorhombic space group D–Pnna (a = 6.518, b = 12.416, c = 8.909 Å). Sr²⁺ is octahedral and most of the Ag⁺ surrounded by weakly angled dumbbells of oxygen. In addition of these configurations metallic regions were found.     

Eu3+ und Eu2+ in Oxometallaten der Zusammensetzung MBeLn2O5: SrBeEu2O5 und EuBeNd2O5

Eu³⁺ and Eu²⁺ in Oxides of the Composition MBeLn₂O₅: SrBeEu₂O₅ and EuBeNd₂O₅ Single crystals of (I): SrBeEu₂O₅ and (II): EuBeNd₂O₅ were prepared by CO₂-LASER (I) in air and plasma torch (II) technique in H₂ atmosphere. X-ray investigations led to orthorhombic symmetry, space group D-Pnma; (I): a = 9.488, b = 7.156, c = 6.495 Å; (II): a = 9.534, b = 7.225, c = 6.544 Å, Z = 4. Sr²⁺ and Eu³⁺ as well as Eu²⁺ and Nd³⁺ are in statistical distribution within a Kagomé framework. Both compounds are discussed with respect to the monoclinic form of MBeLn₂O₅.     

Zur Verbindungsbildung von MeO:M2O3. VI. Darstellung und Strukturaufklärung von Sr1,33 Pb0,67 Al6O11

Compound Formation MeO: M₂O₃. VI. Synthesis and Structure Determination of Sr_1,33 Pb_0,67 Al₆O₁₁ Single crystal of Sr_1,33Pb_0.67Al₆O₁₁ could be prepared with a PbO flux. (Space group D–Pnnm, a = 22.13, b = 4.88, c = 8.42 Å, Z = 4) Sr²⁺ and Pb²⁺ are statistically intercalated into a framework of AlO₆ octahedra and AlO₄ tetrahedra. The typical coordination of Sr²⁺ and Pb²⁺ is realized by occupying different positions in the same cavern.     

Die Kristallstruktur von Perowskiten ANiIIMVIO6. II. Das Sr2NiWO6

The Crystal Structure of Perovskites A Ni^IIM^VIO₆. II. Sr₂NiWO₆ The results of an X-ray single crystal study of the perovskite Sr[Ni^IIW^VI]⁽⁶⁾O₆, ordered in the octahedral sites, are given. While Sr[Ni^IITe^VI]⁽⁶⁾O₆ crystallizes in a monoclinically deformed structure of the perovskite (elpasolite) type, showing a phase transition to a tetragonal lattice at 675 °K, Sr[Ni^IIW^VI]⁽⁶⁾O₆ is tetragonal already at 298°K (space group: C; a = b = 5.559 Å; c = 7.918 Å; Z = 2). The Ni? O distances found for the tungsten compound are nearly identical with those of the tellurium perovskite. In contradiction to crystal field theory very different values of the ligand field parameter Δ (ca. 25%) are observed for these two compounds however. Obviously this effect is caused by the rather different kind of bonding within the NiO₆ polyhedra in the two compounds. On the basis of the structural results the Ni? O-bonding in the two perovskites is discussed in dependence of the next nearest cationic environment.     

Ein weiteres Alkali-Erdalkalimetall-Oxoniccolat mit Perowskitstruktur: Sr12NaNi7O23

Another Alkaline Alkaline-Earth Oxoniccolate of Perovskite Type Structure: Sr₁₂NaNi₇O₂₃ Single Crystals of Sr₁₂NaNi₇O₂₃ were prepared in closed system by Na₂O₂ flux reaction. X-ray single crystal work show hexagonal symmetry, space group D-P321, a = 9.429, c = 7.896 Å, Z = 1. Sr₁₂NaNi₇O₂₃ is strongly related to the stackered perovskites containing consequently face shared Ni₂O₉ double octahedra and Na⁺ inside a trigonal prismatic coordination by oxygen. One underoccupied oxygen point position decreases the coordination number of one Ni³⁺ of the Ni₂O₉ groups and a second surrounded by trigonal prisms to corner connected Ni₂O₇ double tetrahedra. The crystal chemistry will be discussed with respect to compounds of the same structure.     

Ein Neues gemischtvalentes Oxoosmat(VI,VII): Sr11Os26+Os27+O24

A New Mixed Valenced Oxoosmate(VI, VII): Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ . Single crystals of Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ were prepared in closed silver bombs using SrO, osmium and an extend of KO₂. It crystallizes with monoclinic symmetry, space group C–I12/a1 a = 11.703; b = 16.058; c = 11.696 Å; β = 90.03°; Z = 4. Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ shows a new crystal structure characterized by a [Sr₁₁O₂₄]^26? network and incorporated Os⁶⁺ and Os⁷⁺ ions. Calculations of the coulombterm of lattice energy shows an orderer distribution of the two oxidation states of osmium.     

Zur Kristallchemie der Kupfer-Lanthanoid-Oxowolframate: (I) triklin-α-CuTbW2O8, (II) monoklin-CuInW2O8 und (III) monoklin-CuYW2O8

The Crystal Chemistry of Copper Rare-Earth Oxotungstates: (I): triclinic-α-CuTbW₂O₈, (II): monoclinic-CuInW₂O₈ and (III): monoclinic-CuYW₂O₈ Single crystals of (I), (II) and (III) were prepared by recrystallisation in closed systems and examined by X-ray technique. (I): space group C? P1 , a = 7.3080, b = 7.8945, c = 7.1476 Å, α = 115.23, β = 116.21, γ = 56.98°, Z = 2; (II): space group C? C2/c, a = 9.6576, b = 11.6496, c = 4.9863 Å, β = 91.17°, Z = 4; (III): space group C? P2/n, a = 10.0504, b = 5.8214, c = 5.0224 Å, β = 94.23°, Z = 2. The crystal structures are discussed with respect to calculations of the coulombterms of lattice energy and possible valence states of Cu²⁺ and Mo⁵⁺.     

Synthese und Untersuchung von NiNb2O6-Einkristallen mit Columbit- und Rutilstruktur

Synthesis and Investigation of NiNb₂O₆ Single Crystals of Columbite and Rutil Type C-NiNb₂O₆ (columbite type) and R-NiNb₂O₆ (rutil type) single crystals were prepared by solid state reactions. C-NiNb₂O₆ a = 14.032; b = 5.687; c = 5.033 Å, space group D—Pbcn. R-NiNb₂O₆ a = 4.710; c = 3.038 Å, space group D—P4₂/mnm. The metal positions of the rutil structure are statisticaly occupied by Ni²⁺ and Nb⁵⁺ ions. R-NiNb₂O₆ is in respect to lower temperatures a metastable compound.     

Die Photolumineszenz der dreiwertigen Seltenen Erden in den Perowskitstapelvarianten Ba2La2−xSE MgW2□O12, Ba6Y2−xSEW3□O18 und Sr8SrGd2−x SEW4□O24

Photoluminescence of Trivalent Rare Earths in Perovskite Stacking Polytypes Ba₂La_2?x RE MgW₂□O₁₂, Ba₆Y_2?x RE W₃□O₁₈, and Sr₈SrGd_2?xRE W₄□O₂₄ Rhombohedral 12 L stacking polytypes Ba₂La_2?xREMgW₂□O₁₂ show with RE³⁺ = Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm; the 18 L stacking polytypes Ba₆Y_2?xREW₃□O₁₈ and the polymorphic perovskites Sr₈SrGd_2?xREW₄□O₂₄ with RE³⁺ = Sm, Eu, Dy, Ho, Er visible photoluminescence. The concentration dependence and the influence of the coordination number of the rare earth are reported.     

Ein weiteres Gemischtvalentes Oxoniobat: Sr5Nb34+Nb25+O16

About a Mixed Valence Oxoniobate: Sr₅Nb₃⁴⁺Nb₂⁵⁺O₁₆ The hitherto unknown compound Sr₅Nb₅O₁₆ was prepared and examined by X-ray single crystal work. It crystallizes with orthorhombic symmetry (space group D–Pmn2₁, a = 3.992(1), b = 32.476(10), c = 5.677(2) Å; Z = 2). Sr₅Nb₅O₁₆ consists of stacked perovskite-like blocks cut by a plane perpendicular to the cube face diagonal of the perovskite structure. The coordination relations of the intersections between those blocks and the distribution of Nb⁵⁺ and Nb⁴⁺ are discussed.     

Ein neuer Strukturtyp zur Formel ABLn2O5 Zur Kenntnis von BaNiNd2O5

A New Crystal Structure of ABLn₂O₅ Compounds. About BaNiNd₂O₅ The compound BaNiNd₂O₅ was prepared by solid state reaction. Single crystal examination show a new structure type (a = 3.829(2), b = 5.932(3), c = 11.649(3) Å space group D–Immm, Z = 2) with Ni²⁺ in octahedral coordination. The surrounding of Ba²⁺ and Nd³⁺ conforms to BaPtNd₂O₅ with significant differences of the polyhedra connection.     

über Erdalkalimetalloxocuprate,VIII Zur Kenntnis von Sr2CuO2Cl2

On Alkaline Earth Oxocuprates VIII. About Sr₂CuO₂Cl₂ Sr₂CuO₂Cl₂ was prepared and investigated by single crystal X – ray work (space group D–Immm, a = 3.975, c = 15.618 Å). Sr₂CuO₂Cl₂ is isotypic with K₂NiF₄ – compounds and shows an octahedral configuration for Cu²⁺. Cl^? occupies trans-positions of the octahedral Cu²⁺/O^2? polyhedron. A discussion with related compounds (Sr₂CuO₃ and Nd₂CuO₄) explains the observed distribution of O^2? and Cl^?.     

Ein Beitrag über CuPrMo2O8 und CuTbMo2O8

A Contribution on CuPrMo₂O₈ and CuTbMo₂O₈ Single crystals of (I): CuPrMo₂O₈ and (II): CuTbMo₂O₈ were prepared by solid state reactions in closed copper tubes. They crystallize with orthorhombic symmetry, space group D-Pbca, (I): a = 10.4114, b = 9.8917, c = 14.8287 Å, (II): a = 10.2243, b = 9.7385, c = 14.6000, Z = 8. Both compounds are isotypic to CuYMo₂O₈, showing isolated MoO₄ tetrahedra, square antiprismatic coordination of Ln³⁺ and Cu⁺ besides one edge of an O^2? triangle. Calculations of the coulombterm of lattice energy support the oxidation state Cu²⁺ in combination with mixed valences of Mo⁶⁺ and Mo⁵⁺ on the molybdenum point positions.     

Über Erdalkalimetalloxogallate. III. Untersuchung des Aufbaus von CaGa2O4

On Alkaline Earth Oxogallate. III. Investigation of the Structure of CaGa₂O₄ Single crystals of CaGa₂O₄ were prepared and investigated by X-ray goniometer data: a = 10.89, b = 7,725, c = 9,032 Å. Space group C? Pna2₁. Ga³⁺ is tetrahedrally surrounded by oxygen. Ca²⁺ has an irregular oxygen coordination. CaGa₂O₄ is a new member of the stuffed silicate structures.     

Zur Kristallstruktur von Cu2M(BO3)O2 (M = Fe3+, Ga3+)

The Crystal Structure of Cu₂M(BO₃)O₂ (M = Fe³⁺, Ga³⁺) Single Crystals of the compounds Cu₂M(BO₃)O₂ (M = Fe³⁺ (I), Ga³⁺ (II)) were obtained by a B₂O₃ flux-technique. They crystallize in a monoclinic distorted variant of a Ludwigite structure with a partly ordered metal distribution. X-ray investigations on single crystals led to the space group C–P2₁/c (No. 14); I: a = 3.108(1); b = 12.003(1); c = 9.459(3) Å; b? = 96.66(3)°; Z = 4 and II: a = 3.1146(2); b = 11.921(3); c = 9.477(2) Å; b? = 97.91(2)°; Z = 4. All metal-sites are distorted octahedraly coordinated by oxygen-ions. The structure contains isolated planar BO₃-units and oxygen which is not coordinated to boron.     

Ba2BiV3O11 mit Bismut in geschlossener Koordination

Ba₂BiV₃O₁₁ containing Bismuth within closed Coordination A new barium bismuth oxovanadate, Ba₂BiV₃O₁₁, was prepared and investigated by X-Ray single crystal technique. It crystallizes with monoclinic symmetry space group C—P2₁/a, lattice constants a = 24.6473; b = 7.7347; c = 5.6375 Å, β = 103.16°; Z = 4. Octahedra arround Bi³⁺, tetrahedra and double tetrahedra arround V⁵⁺ form a tunnel structure. The tunnel positions are occupied by Ba(2).     

Zur Kristallstruktur von Ca2PbO4

On the Crystal Structure of Ca₂PbO₄ Single crystals of Ca₂PbO₄ were prepared by flux technique and investigated by X-ray methods. It crystallizes with orthorhombic symmetry, space group D-Pbam. (a = 5.832; b = 9.766; c = 3.375 Å, Z = 2.) Ca₂PbO₄ belongs to the Sr₂PbO₄ type. It shows Ca²⁺ in a seven fold and Pb⁴⁺ in octahedral coordination.     

Ein Beitrag zur Kristallchemie von BaBiO3

A Contribution on the Crystal Chemistry of BaBiO₃ Single crystals of BaBiO₃ were prepared and investigated by X-Ray methods (a = 436.4, c = 451.8 pm, space group D–P4 2m). It was found a statistical distribution of Ba²⁺ and O^2?, which leads to different distances in the Bi? O surrounding. A discussion of two possible polyhedral configurations in respect to the valence of Bi is given.     

Ein neuer Strukturtyp bei Kupfer-Lanthanoid-Oxowolframaten: CuDy5(WO4)8

A New Structure Type of Copper Lanthanoide Oxotungstates: CuDy₅(WO₄)₈ Single crystals of the hitherto unknown compound CuDy₅(WO₄)₈ were prepared in closed copper tubes and investigated by X-ray technique. It shows monoclinic symmetry, space group C—C2/c, a = 19.118, b = 5.612, c = 11.518 Å, β = 111.32°, Z = 2. The crystal structure is characterized by [W₄O₁₈] groups which are connected to layers. Dy³⁺ shows one sided capped trigonal prisms and Cu⁺/Dy³⁺ with statistical distribution an octahedral oxygen surrounding.