Die Kristallstrukturen der hexagonalen Elpasolithe Ba3NiSb2O9 und Ba3CuSb2O9 – röntgenographische und spektroskopische Ergebnisse

The Structures of the Hexagonal Elpasolite-Type Compounds Ba₃NiSb₂O₉ and Ba₃CuSb₂O₉ The results of an X-ray single crystal study of the hexagonal elpasolite Ba(NiSb₂)⁽⁶⁾O₉ are given. (Space group: C; a = b = 5.837 Å, c = 14.392 Å; Z = 2). The structure can be described by close-packed BaO₃ layers alternating in the sequence c c h c c h … (hex. BaTiO₃ type). Groups of two octahedra with common faces are connected by SbO₆ octahedra via common corners. They are occupied alternately by Ni and Sb. The final reliability index was R = 3.0%. The Cu²⁺-compound is of the same structural type. The ligand field and EPR spectra are discussed in comparison with related Ni²⁺ and Cu²⁺ compounds.     

Über Erdalkalimetalloxothallate. II. Darstellung und Kristallstruktur von Ba2Tl2O5

On Alkaline Earth Metal Oxothallates. II. Preparation and Crystal Structure of Ba₂Tl₂O₅ Ba₂Tl₂O₅ was prepared and investigated by X-ray single crystal methods (space group D? Pcmn, a = 6.264, b = 17.258, c = 6.05 Å) Ba₂Tl₂O₅ is isotypic with Ca₂Fe₂O₅.     

Über hexagonale Perowskite mit Kationenfehlstellen. XXIV. Rhomboedrische 9 L-Stapelvarianten in den Systemen Ba3W M □ O9−x/2□x/2 mit MV = Nb,Ta

On Hexagonal Perovskites with Cationic Vacancies. XXIV. Rhombohedral 9 L Stacking Polytypes in the Systems Ba₃W M □O_9?x/2□_x?2 with M^V = Nb, Ta In the system Ba₃WNb□O_9?x/2□_x/2 stacking polytypes of rhombohedral 9 L type (sequence (hhc)₃; space group R3 m) can be prepared with ～1/3 ? × ? 2. For x = 2(Ba₃Nb₂□O₈□) two modifications are formed. In the corresponding Ta system the phase with is reduced to a smaller region with x ? 1/3.     

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).     

Über hexagonale Perowskite mit Kationenfehlstellen. XXVI. Ba12Ba2 2/3M 1/3□2O33□3 (MV = Nb,Ta) – die ersten Stapelvarianten eines rhomboedrischen 36 L-Typs

On Hexagonal Perovskites with Cationic Vacancies. XXVI. Ba₁₂Ba_{2 2/3}M _1/3□₂O₃₃□₃ (M^V = Nb, Ta) – the First Stacking Polytypes of a Rhombohedral 36 L-Type In the systems BaO? MO₅(M^V = Nb, Ta) for a Ba:M^V ratio of 2:1 polymorphism is observed. Here the low temperature modifications are described. They crystallize in a rhombohedral 36 L structure with three formula units Ba₁₂Ba_{2 2/3}M _1/3□₂O₃₃□₃ for the trigonal setting (M^V = Nb: a = 5.92₂ Å; c = 93.₂₅ Å; Ta: a = 5,92₂ Å; s = 93.4 Å).     

Synthese und Kristallstruktur von Ba6Lu4Zn10O22 mit [OBa6]-Oktaedern

On the Synthesis and Crystal Structure of Ba₆Lu₄Zn₁₀O₂₂ with [OBa₆] Octahedra Single crystals of Ba₆Lu₄Zn₁₀O₂₂ have been prepared by high temperature reactions and investigated by X-ray techniques. This compound is isotypic to Ba₃In₂Zn₅O₁₁ and the first member of the Rare Earth elements. Ba₆Lu₄Zn₁₀O₂₂ crystallizes with cubic symmetry, space group T-F4 3m, a = 13.452(1) Å and Z = 4. Zn²⁺ shows a tetrahedral, Lu³⁺ an octahedral and Ba²⁺ a three-fold capped trigonal prismatic coordination by O^2?. The ZnO₄ tetrahedra and LuO₆ octahedra are forming macro polyhedra of the type Zn₁₀O₂₀ and Lu₄O₁₆. A discussion is given for the Ba₆O₃₃ and Ba₆O₄₂ groups.     

Über hexagonale Perowskite mit Kationenfehlstellen. XVI Die rhomboedrischen 12 L-Stapelvarianten Ba3AIIIM□O12 mit MV = Nb,Ta

On Hexagonal Perovskites with Cationic Vacancies. XVI. Rhombohedral 12 L-Stacking Polytypes Ba₃A^IIIM □O₁₂ with M^V = Nb, Ta The white quaternary oxides Ba₃LaM□O₁₂ with M^V = Nb, Ta belong to the group of hexagonal perovskites with cationic vacancies. They crystallize in a rhombohedral 12 L-structure (sequence (hhcc)₃; space group R3 m) with a = 5.75₁ Å; c = 28.1₁ Å (M^V = Nb); a = 5.74₆ Å; c = 28.2₀ Å (Ta) and Z = 3. Signs for the formation of isotypic compounds with A^III = Pr, Nd could be obtained as well.     

Ba6CoNb9O30: Ein neuer Vertreter der tetragonalen Wolframbronzen

Ba₆CoNb₉O₃₀: A New Compound of the Tetragonal Bronze Structure The hitherto unknown compound Ba₆CoNb₉O₃₀ was examined by X-ray single crystal work. (Space group C-P4bm; a = 1258.9; c = 400.9 pm) Co³⁺ and Nb⁵⁺ occupy a special position in an octahedral framework. The coordination of Ba²⁺ is discussed.     

Mononuclear Thiolatecobalt Carbonyls

A Partial Statistically Incorporation of Ca²⁺ into the Ba₆Nd₂Al₄O₁₅-Type: Ba₅CaLa₂Fe₄O₁₅ Using high temperature reactions we succeeded in incorporating Ca²⁺ into the Ba₆Nd₂Al₄O₁₅ type. Single crystal X-ray methods reveal a partly ordered alkaline earth distribution. Ba²⁺ and Ca²⁺ occupy face connected MO₆-octahedra as well as a further point position together with La³⁺ ions (space group C−P6₃mc; a = 11.770; c = 7.039 Å; Z = 2).     

Die Kristallstruktur der Hexagonalen Verbindungen BaMeIISbO9. II. Ba3CuSb2O9

Crystal Structure of the Hexagonal Compounds Ba^II₃Me^IISb^v₂O₉. II. Ba₃CuSb₂O₉ The crystal structure of the compound Ba₃CuSb₂O₉ was determined from single crystal X-ray diffraction data and refined down to R = 0.03. Ba₃CuSb₂O₉ crystallizes in the hexagonal space group P6₃mc (C) with a = b = 5.809 Å, C = 14.321 Å and Z = 2. The structure can be described by close–packed BaO₃ layers in the sequence cchcchcch…?(hex. BaTiO₃ type). Groups of two octahedra with common faces are connected by SbO₆ octahedra via common corners. They are occupied alternately by Cu and Sb. In agreement with the EPR spectra the CuO₆-octahedra present no static Jahn-Teller distortion at room temperature. However the thermal ellipsoids of the oxygen atoms indicate the presence of adynamic Jahn-Teller-effect.     

Über Ruthenium-Perowskite vom Typ Ba2BRuO6 und Ba3BRu2O9 mit B = Indium,Rhodium

On Ruthenium perovskites of type Ba₂BRuO₆ and Ba₃BRu₂O₉ with B = Indium, Rhodium The black perovskites Ba₂InRu⁵⁺O₆ and Ba₃InRu₂O₉ (mean oxydation state of ruthenium: +4.5) adopt the hexagonal BaTiO₃ structure and form a continuous series of mixed crystals. According to the intensity calculations and analysis of the vibrational spectroscopic data an ordered distribution between indium and ruthenium is present: 1:1 order in Ba₂InRuO₆ (space group P3 m1 ? D; R′ = 5.3%); 1:2 order in Ba₃InRu₂O₉ (space group P6₃/mmc ? D; R′ = 4.6%). The corresponding black Rh compounds, Ba₂RhRuO₆ and Ba₃RhRu₂O₉, crystallize in the rhombohedral 9 L type of BaRuO₃.     

Zur Atomverteilung in Ba2SrIn2O6 mit einem Beitrag zur Existenz des Calciumferrat(III)-Typs bei Oxoindaten

On the Atomic Distribution in Ba₂SrIn₂O₆ with a Contribution to the Existence of the Calciumferrite-Type of Oxoindates (I) Ba₂SrIn₂O₆ and (II) Sr_0.93Ba_0.07In₂O₄ were prepared and investigated by single crystal X-ray technique. I crystallizes with tetragonal symmetry, space group D – I4/mmm, a = 4.168; c = 21.290 Å; Z = 2; II belongs to the orthorhombic space group D – Pnma, a = 9.858; b = 3.273; c = 11.520 Å; Z = 4. I shows in respect to the formerly investigated compound BaSr₂In₂O₆ an unexpected statistically distribution of Ba²⁺ and Sr²⁺ with the La₂SrCu₂O₆ type. II marks the range of existence of the calciumferrite type within the alkaline earth oxoindates in direction of large radii of M²⁺ ions.     

Über hexagonale Perowskite mit Kationenfehlstellen. XXXI. Die Systeme BaO?Re2O7?MO5 mit MV = Nb,Ta

On Hexagonal Perovskites with Cationic Vacancies. XXXI. Systems BaO? Re₂O₇? M O₅ with M^V = Nb, Ta In the systems BaO? Re₂O₇? MO₅ three quaternary oxides are formed, which belong to the perovskite stacking polytypes with cationic vacancies: Ba₈Re_7/2M□₃O₂₄ (M^V = Nb, Ta; rhombohedral 24 L type; sequence (hhhhchhc)₃; space group R3 m), Ba₄Re_9/8Ta_13/8□_5/4O₁₂ (rhombohedral 12 L type; sequence (hhcc)₃; space group R3 m) and the phases Ba₅BaRe_3/2?xM □O_15?x□_x (M^V = Nb, Ta; variants of a hexagonal 5 L type).     

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 neues Oxometallat mit Mangan(II): Ba5Mn4Nd8O21

On a New Oxometallate of Manganese (II): Ba₅Mn₄Nd₈O₂₁ Single crystals of Ba₅Mn₄Nd₈O₂₁ were prepared for the first time by CO₂-Laser technique using H₂-atmosphere. It was investigated by a single crystal X-ray diffractometer study. Ba₅Mn₄Nd₈O₂₁ crystallizes with tetragonal symmetry space group: C? I4/m; a = 14.2104 Å; c = 5.8581 Å; Z = 2. Mn²⁺ is found in square pyramids of oxygen.     

Ein neuer Strukturtyp eines neuen Ruthenium(V)-Oxidchlorids: Ba5Ru2O9Cl2

Ba₅Ru₂O₉Cl₂ — a New Structure Type of a New Ruthenium(V) Oxidechloride For the first time an alkaline earth-halogenooxo-ruthenate(V) with the formula Ba₅Ru₂O₉Cl₂ was prepared and investigated by X-ray single crystal technique. It builds up a new type of structure with an orthorhombic symmetrie (space group D—Pnma, a = 15.310; b = 5.945; c = 14.197 Å). The crystal structure show a threedimensional Ba/O/Cl frame, which contains isolated Ru₂O₉-double-octahedra. The relations to other structures are discussed.     

Zur Kristallstruktur von Ba2ZnO3

On the Crystal Structure of Ba₂ZnO₃ Single crystals of Ba₂ZnO₃ were prepared by solid state reaction. It crystallizes monoclinic: space group C ? C12/c1; a = 5.833; b = 11.376; c = 12.585 Å; β = 93.63°; Z = 8. The crystal structure is characterised by [ZnO₃] chains along [100]. They are connected by Ba²⁺ in seven fold oxygen coordination.     

Über Hexagonale Perowskite mit Kationenfehlstellen. I. Verbindungen vom Typ Ba2B□2/3ReVIIO6

On Hexagonal Perovskites with Cationic Vacancies. I. Compounds of the Type Ba₂B □_2/3Re^VIIO₆ Compounds of Type Ba₂B□_2/3Re^VIIO₆ are formed with B^III = Sm? Gd Ho? Lu, Y, Sc, In (yellow); Tb (black-brown); Dy (yellow-orange). They crystallize with B^III = Sm? Lu, Y and Sc in a rhombohedral layer structure of 12 L-type (space group R3 m; sequence: cchhcchhcchh) with 6 formula units in the unit cell.     

Zwei neue Verbindungen mit Zink in tetragonal pyramidaler Koordination: BaZnDy2O5 und Ba1,25ZnHo2O5,25 (Ba5Zn4Ho8O21)

New Compounds with Zinc in Square Pyramidal Coordination: BaZnDy₂O₅ and Ba_1.25ZnHo₂O_5.25 (Ba₅Zn₄Ho₈O₂₁). Single crystals of (I): BaZnDy₂O₅ and (II): Ba₅Zn₄Ho₈O₂₁ were prepared by high temperature reactions and investigated by X-ray technique. (I) belongs to the BaCuLn₂O₅ type, space group D-Pbnm; a = 7.084; b = 12.368; c = 5.728 Å, Z = 4. (II) is isotypic to Ba₅Mn₄Ln₈O₂₁, space group C-I4/m; a = 13.779; c = 5.707 Å, Z = 2. The two different structure types are caused by the small difference in the composition of 0.25 BaO. Analogies and differences will be discussed. In addition the lattice constants of powder samples of Ba₅Zn₄Ln₈O₂₁ (Ln = Eu, Gd, Dy, Ho, Er and Y) are given.     

Über hexagonale Perowskite mit Kationenfehlstellen. XXX. 5 L-Stapelvarianten in den Systemen BaO?Re2O7?Sb2O5 und BaO?WO3?Sb2O5

On Hexagonal Perovskites with Cationic Vacancies. XXX. 5 L Stacking Polytypes in the Systems BaO — Re₂O₇? Sb₂O₅ and BaO? WO₃? Sb₂O₅ In the systems BaO? Re₂O₇? Sb₂O₅ and BaO? WO₃? Sb₂O₅ phases of composition Ba₅BaRe Sb□O_15?x□_x (x = 0 up to x ? 3/4) and Ba₅BaWSb□O_15?x/2□_x/2 (x ? 3/2 up to x ? 2) are existent, which have an orthorhombic distorted 5 L structure. The pure Sb compound has to be formulated as Ba₃BaSb₂O₉ and crystallize in an orthorhombic variant of the hexagonal BaTiO₃ type.