Rb2TiO3, ein neues Oxotitanat mit der Koordinationszahl 4

Rb₂TiO₃, a New Oxotitanate with Coordination Number 4 Rb₂TiO₃ cristallizes according to single crystal datas [544 Okl? 4kl, Mo? Kα] orthorhombic, a = 6.01₅, b = 11.93₆, c = 13.36₆ Å, Z = 8, space group D? Cmca, d_rö = 3.69, d_pyk = 3.65 g cm^?3; for occupied positions and atomic parameters see text. Surprisingly the coordination number of Ti to 0 turns out to be 4. The chains [TiO_1/1O_1/1O_2/2] are placed along [100]. The Madelung part of lattice energy (MAPLE) of Rb₂TiO₃ is calculated and discussed. In order to display the characteristics of the structure, further MAPLE-calculations have been carried out. K₂TiO₃ belongs to the Cs₂PbO₃-Family of structure with C.N. 5 of Ti to 0. Cs₂TiO₃ and Rb₂TiO₃ are not isotypic.     

Über quaternäre Oxoplumbate(IV). Zur Kenntnis von Rb3NaPbO4

On Quaternary Oxoplumbates(IV). On Rb₃NaPbO₄ For the first time, Rb₃NaPbO₄ has been prepared by annealing mixtures of Na₂PbO₃ and RbO_0.84 with Rb:Na:Pb = 4:2:1 [nonhermetic Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 480°C, 180 d (single crystals)]. The colourless crystals are of squatted shape. The structure determination [2943 symmetry independent hkl, four-circle-diffractometer PW 1100 (Fa. Philips), ω-2Θ-scan, AgKα, R = 8.64%, R_W = 6.59%, absorption not considered] confirms the space group P2₁/c with a = 1101.79(26), b = 662.66(11), c = 1115.01(30) pm, β 112.027(21)°. The structure is characterized by isolated [PbO₄]-tetrahedra and [Na₂O₆]-tetrahedra-doubletts, C.N. 5 and 7 for Rb⁺. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Die ersten Oxocobaltate(II) mit zweikernigem Anion: Rb2Na4[Co2O5] und K2Na4[Co2O5]

The First Oxocobaltate(II) with Dinuclear Anion: Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] By heating of well ground mixtures of the binary oxides [A₂O, Na₂O, ?CoO”?, A:Na:Co = 1.00:2.00:1, (A = K, Rb); Ag-tube, 600°C, 14 d] we obtained Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] rough, transparent, red single crystals. We find a new type of structure with the anion [O₂CoOCoO₂]^6?. Space group P4₂/mnm; a = 634.4 pm, c = 1030.3 pm, Z = 2 (A = K) a = 647.6 pm, c = 1021.1 pm, Z = 2 (A = Rb); four-circle diffractometer data; MoKα -radiation; 360 from 364 I₀(hkl), R = 4.34%, R_w = 3.54% (A = K); 361 from 366 I₀(hkl), R = 6.54%, R_w = 2.70% (A = Rb). The anion is planar, the CN of Co is 3. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, are calculated and discussed.     

Über quaternäre Oxoplumbate(IV). Zur Kenntnis von Rb2Li14[Pb3O14] und Cs2Li14[Pb3O14]

On Quaternary Oxoplumbates(IV). On the Knowledge of Rb₂Li₁₄[Pb₃O₁₄] and Cs₂Li₁₄[Pb₃O₁₄] For the first time, Rb₂Li₁₄[Pb₃O₁₄] and Cs₂Li₁₄[Pb₃O₁₄] have been prepared by heating of mixtures of Li₂O, β-?PbO₂”? and Rb₂PbO₃, Cs₂PbO₃ respectively with Li:Pb:A = 14:3:2, (A = Rb, Cs). [Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 590 and 550°C, 40 d, powder (650°C, 200 d, single crystals of Rb₂Li₁₄[Pb₃O₁₄])]. Rb₂Li₁₄[Pb₃O₁₄] is nearly colourless with ivory nuance, Cs₂Li₁₄[Pb₃O₁₄] is pale yellow. According to powder and single crystal investigations, both are isotypic with K₂Li₁₄[Pb₃O₁₄]. Structure refinement of Rb₂Li₁₄[Pb₃O₁₄]: 1015 symmetry independent reflexions, four-circle-diffraktometer PW 1100 (Fa. Philips), ω-scan, MoKα, R = 5.73%, R_W = 5.33%, absorption not considered, space group Immm with a = 1284.71(9), b = 793.90(4), c = 727,35(5) pm, d_x-ray = 4.99 g · cm^?3, d_pyc = 5.01 g · cm^?3, Z = 2. Cs₂Li₁₄[Pb₃O₁₄]: a = 1295.28(12), b = 796.69(8), c = 732.44(7) pm, d_x-ray = 5.31 g · cm^?3, d_pyc = 5.28 g · cm^?3, Z = 2. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Über gemischtvalente Oxoplumbate. Zur Kenntnis von Rb2Pb4O7 = Rb2PbPbO7

On Mixed-valent Oxoplumbates. On Rb₂Pb₄O₇ = Rb₂Pb Pb O₇ For the first time, Rb₂Pb₄O₇ has been prepared by annealing mixtures of Rb₂O₃ and PbO with Rb:Pb = 1:2 [Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 450°C, 30 d (single crystals)]. The rubin red single crystals are of longish [001] shape. The structure determination [5162 symmetry independent hkl, four-circle-diffractometer CAD 4 (Fa. Enraf-Nonius), ω-2Θ—scan, AgKα, ψ-scan absorption correction, R = 7.54%, R_W = 7.71%] confirms the space group P1 with a = 1036.00(10), b = 733.72(8), c = 663.54(10) pm, α = 90.049(12)°, β = 99.236(12)°, γ = 101.641(12)°, Z = 2, d_rö = 7,58 g · cm^?3, d_pyk = 7,55 g · cm^?3. The structure is characterized by a layer-lattice. The coordination number is three for Pb²⁺, six for Pb⁴⁺. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Neue Elpasolithvertreter mit CoIII: Cs2KCoF6, Rb2KCoF6, Rb2NaCoF6 (mit einer Notiz über Cs2NaCoF6)

New Elpasolithes with Co^III: Cs₂KCoF₆, Rb₂KCoF₆, Rb₂NaCoF₆ (with a Notice on Cs₂NaCoF₆) New prepared are the compounds Cs₂KCoF₆ (a = 8.97₉ Å), Rb₂KCoF₆ (a = 8.80₉ Å), Rb₂NaCoF₆ (a = 8.42₁ Å), all cubic Elpasolithes, as well as Cs₂NaCoF₆ (Cs₂NaCrF₆?type, hexagonal with a = 6.23, c = 30.32 Å) all of light blue colour. Cs₂KCoF₆ (72.7–299.7 K) and Rb₂KCoF₆ (71.4–298.0 K) have been measured magnetically. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed.     

Neue Oxozincate der Alkalimetalle: Rb2[ZnO2] und Cs2[ZnO2]

New Oxozineates of Alkali Metals: Rb₂[ZnO₂] and Cs₂[ZnO₂] Colorless single crystals of the hitherto unknown Rb₂[ZnO₂] (a = 9.55₈, b = 6.33₅, c = 15.91 Å, β = 118.6°, z = 8, d_pyk = 4.11, d_rö = 4.21 g · cm^?3) and Cs₂[ZnO₂] (a = 9.85₁, b = 6.61₉, c = 16.26 Å, β = 116.8°) have been prepared, which crystallize monoclinic, P2₁/c – D. (For parameters see text.) Unexpected there are “isolated” groups [Zn₄O₈]. Half of the Zn atoms exhibit the unusual coordination number 3 towards O^2?. The Madelung Part of Lattice Energy, MAPLE, and the Effective Coordination Number, ECoN, the latter by means of Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.     

Neue Oxoplumbate(II) A2PbO2 (A = K,Rb, Cs) mit zweikernigen Gruppen [OPbO2PbO]

New Oxoplumbates(II) A₂PbO₂ (A = K, Rb, Cs), with Binuclear Groups [OPbO₂PbO] Unknown K₂PbO₂, Rb₂PbO₂ and Cs₂PbO₂ (yellowish powder, yellowish transparent single crystals, respectively) have been prepared, The compounds crystallize triclinic with a = 10.90₁ Å, b = 7.60₆ Å, c = 7.32₈ Å, α = 119.3₅°, β = 88.4₂°, γ =117,7₃°, (K₂PbO₂); a = 10.90₇ Å, b = 8.51₀ Å, c = 7.81₅ Å, α = 124.0₀°, β = 84.9₇°, γ = 120.6₈° (Rb₂PbO₂) and a = 11.64₄ Å, b = 8.90₅ Å, c = 8.04₀ Å, α = 123.3₂°, β = 85.7₀°, γ = 120.4₉° Z = 4, space group P1 -C/_i¹. For K₂PbO₂ we find R = 8.6₅% and R_w = 9.3₂% (2283 independent reflections). Parameters see text. There are isolated [Pb₂O₄]groups, which are connected in a complicated way by mutual K⁺ ions forming layers. The Madelung Part of the Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these by means of mean Fictive Ionic Radii, MEFIR, are calculated and discussed.     

Ein neues Oxogermanat: Li8GeO6 = Li8O2[GeO4]. (Mit einer Bemerkung über Li8SiO6 und Li4GeO4)

A New Oxogermanate: Li₈GeO₆ ? Li₈O[GeO₄] Transparent colourless single crystals of Li₈GeO₆(P6₃cm, a = 550.09(8), c = 1072.2(3) pm, Z = 2; 4-circle-diffractometer Siemens AED 2, MoKα; 326 I_o(hkl), R = 2.4%, R_w = 2.0%), have been prepared. As by-product we always got colourless isometric single crystals of Li₄GeO₄. For the first time we could grow single crystals of Li₈SiO₆ of suitable size and quality. Our structure refinement confirms the assumed structure model [2]: Li₈GeO₆ and Li₈SiO₆ are isotypic with Li₈CoO₆[3] (Li₈SiO₆: a = 542.43(8), c = 1062.6(2) pm, Z = 2; 4-circle-diffractometer Siemens AED 2, MoK_α; 306 I_o(hkl), R = 3.6%, R_w= 3.0%). The known crystal structure of Li₄GeO₄ [4] is confirmed and refined (Cmcm, a = 776.6(2), b = 735.7(3), c = 604.9(2) pm, Z = 4; 4-circle-diffractometer Siemens AED 2, MoKα, 298 I_o(hkl), R = 1.9%, R_w = 1.4%). The Madelung Part of Lattice Energy, MAPLE, and Effective coordination-Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.