Über Oxide mit dem “Butterfly-Motiv”: Rb6[Fe2O5] und K6[Fe2O5]

New Oxides with the “Butterfly-Motive”: Rb₆[Fe₂O₅] and K₆[Fe₂O₅] Rb₆[Fe₂O₅] and K₆[Fe₂O₅] were obtained for the first time by annealing intimate mixtures of “Rb₆CdO₄” with CdO (molar ratio 1 : 1.1) and KO_0.48 with CdO (molar ratio 5.9 : 1) respectively in closed Fe-cylinders. Determination and refinement of the crystalstructure confirms the space group C2/m (four-circle-diffractometer data). Rb₆[Fe₂O₅]: Ag Kα , 720 out of 1220 Io(hkl), R = 9.68%, R_w = 6.09%; a = 718.9pm, b = 1183.1 pm, c = 695.4pm, β = 95.05°, Z = 2; K₆[Fe₂O₅]: MoKα , 1214 Out of 12141_o(hkl), R = 3.20070, R_w = 2.48%, a = 691.21 pm, b = 1142.78pm, c = 665.50pm, β = 93.82°, Z = 2. The binuclear unit [O₂FeOFeO₂]^6? already known to be planar with oxoferrates(II) now was observed to be angular here and closely related to Na₆[Be₂O₅].     

Das erste zweikernige Oxoferrat(II): „Cs2K4[O2FeOFeO2]”︁

The First Binuclear Oxoferrate(II): ?Cs₂K₄[O₂FeOFeO₂]”? For the first time ?Cs₂K₄[Fe₂O₅]”? was obtained by annealing intimate mixtures of Cs₂O, K₂O, and CsFeO₂ (molar ratio Cs : K : CsFeO₂ 1.3 : 2.1 : 1) in a closed Fe-cylinder (74 d; 470°C) in the form of red single crystals. The structure determination (four-circle diffractometer, MoKα , 760 out of 857 I_o(h kl); R = 5.8%, R_w = 4.6%) confirms the space group C2/m; a = 707.4, b = 1138.5, c = 699.7 pm, β = 91.76°, Z = 2. Essential part of the structure is the binuclear, planar [O(1)₂Fe? O(2)? FeO(1)₂]^6? group which is for the first time observed with oxoferrates(II). Despite different space groups the crystal structure is related to that of Rb₂Na₄[Co₂O₅].     

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.     

Zur Kenntnis von Unordnungsphänomenen bei Oxiden mit dem „Schmetterlingsmotiv”︁ Über Rb2K4[O2CoOCoO2]

On the Knowledge of Disorder Phenomena in Oxides with the Motive of Butterfly. On Rb₂K₄[O₂CoOCoO₂] For the first time Rb₂K₄Co₂O₅ was obtained by annealing intimate mixtures of the binary oxides as dark red single crystals (Rb:K:Co = 1.2:3.2:1; Ni-tube; 570°C; 20 d). Structure Refinement [fourcircle diffractometer data; PW 1100; AgK radiation; 401 of 607 I₀(hkl); R = 9.9%; R_w = 5.5%; space group P4₂/mnm; Z = 2; a = 674,2(4), c = 1172,2(6) pm] confirms the isotypism to K₂Na₄Co₂O₅, Rb₂Na₄Co₂O₅ [2] and K₂Na₄Be₂O₅ [3]. The Madelung Part of Lattice Energy, MAPLE, Effektive Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, and the Charge Distribution, ΣQ, were calculated. The isotypism of Rb₂K₄Co₂O₅ and Rb₂Na₄Co₂O₅ is compared graphically.     

Neues über Zweikernige Oxoferrate(II)

News about Binuclear Oxoferrates(II) [1] . By “reaction with the wall” of the Fe-cylinders used here we synthesized the new oxoferrates(II) Cs₆[Fe₂O₅], Cs_3.5Rb_2.5[Fe₂O₅] and Rb₄K₂[Fe₂O₅] in the form of red single crystals. The structure elucidation via four-circle-diffractometer data shows that the new oxoferrates(II) are isotypic with Cs₂(Cs_0.35K_1.65)K₂ [Fe₂O₅]. In the structure we have isolated binuclear groups [(O1)₂Fe—O(2)—Fe(O1)₂]^6?. Structure refinements is possible in the centrosymmetrial space group C2/m as well as in the space groups C2 and Cm without centre of symmetry. The existence of two further oxoferrates(II) Cs_6?xRb_x[Fe₂O₅] and Cs_6?xK_x[Fe₂O₅] which can be described as solid solutions was confirmed by power-data.     

Ein neues Oxoberyllat: K2Na4[O2BeOBeO2]

On K₂Na₄[O₂BeOBeO₂] For the first time colourless single crystals of K₂Na₄[Be₂O₅] which are isotypic with K₂Na₄[Co₂O₅] [2] and Rb₂Na₄[Co₂O₅] have been prepared by heating e.g. a well ground mixture of K₂O, Na₂O and BeO (K:Na:Be = 2.2:4.4:2; 750°C; 21 d; Ni-tube). The crystal structure was solved by four-circle diffractometer data [Siemens AED 2; 389 I_o(hkl); space group P4₂/mnm; Z = 2; a = 595.17(4) pm, c = 1 002.66(9) pm; R = 4.1%; R_w = 2.3%]. Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, the Madelung Part of Lattice Energy, MAPLE, and the charge distribution are calculated.     

Synthese,Kristallstrukturen und Absorptionsspektren der neuen „Cupriosilicate”︁: K6[CuSi2O8] und Rb4[CuSi2O7]

Synthesis, Crystal Structures, and Absorption Spectra of the New “Cupriosilicates”: K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] were obtained by annealing intimate mixtures of K₂O and Rb₂O, respectively, CuO and SiO₂ in sealed Ag cylinders at 500°C as transparent greenish-blue single crystals. The structure solution (IPDS-data Mo Kα; K₆[CuSi₂O₈]: 1292 F²(hkl), R1 = 0.059; wR2 = 0.103 and Rb₄[CuSi₂O₇]: 763 F²(hkl), R1 = 0.049; wR2 = 0.114) confirms the space group P1 for both compounds. K₆[CuSi₂O₈]: a = 619.4(2); b = 665.5(2); c = 753.0(2) pm; α = 83.66(3); β = 87.71(3); γ = 70.19(3)°; Z = 1. Rb₄[CuSi₂O₇]: a = 631.9(9); b = 707.5(10); c = 715.2(6) pm; α = 114.2(1); β = 100.7(1); γ = 107.9(1)°; Z = 1. The Madelung Part of the Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these calculated via Mean Effective Ionic Radii, MEFIR, are given. The absorption spectra of K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] are discussed in terms of the Angular Overlap Model, AOM.     

Das gemischtvalente ternäre Oxoferrat(II,III) K3[Fe2O4] – eine aufgefüllte Variante des K2[Fe2O4]‐Typs

The Mixed‐Valent Oxoferrate(II,III) K₃[Fe₂O₄] – A Stuffed Variant of the K₂[Fe₂O₄] Type of Structure K₃[Fe₂O₄] has been obtained by tempering “Cs₃K₃CdO₄” in sealed Fe containers (36 d at 450–480 °C) as dark red transparent single crystals of rectangular shape. The structure determination (IPDS diffractometer data, MoKα, 1891 collected reflections, 234 symmetry independent, R1 = 0.033, wR2 = 0.088) confirms the space group Fddd; a = 596.11(9), b = 1140.3(1), c = 1717.9(3) pm; Z = 8. K₃[Fe₂O₄] exhibits a structure with [FeO₄] tetrahedra connected via corners leading to a three‐dimensional network closely related to the KFeO₂ type of structure. From the oxidation at 520 °C of iron metal with KO₂ in the presence of Na₂O black single crystal of K₂[Fe₂O₄] have been obtained. K₂[Fe₂O₄] crystallizes in the space group Pbca with Z = 8 and a = 559.18(7), b = 1122.1(1), c = 1592.8(2) pm (IPDS diffractometer data, MoKα, collected refelctions: 9543, 1213 symmetry independent, R1 = 0.043, wR2 = 0.102).     

Neue Oxogallate der Alkalimetalle: Über K6[Ga2O6] und Rb6[Ga2O6], sowie Na3GaO3 und Cs6[Ga2O6]

New Oxogallates of Alkaline Metals: On K₆[Ga₂O₆] and Rb₆[Ga₂O₆] as well as Na₃GaO₃ and Cs₆[Ga₂O₆] Due to powder and single crystal data K₆[Ga₂O₆] a = 7.09₉; b = 11.11₆; c = 6.48₄ Å; ß = 101.6₆° and Rb₆[Ga₂O₆] a = 7.39₃; b = 11.47₅; c = 6.79₈ Å; ß = 103.5° crystallize isotypic with K₆[Fe₂O₆]; space group C2/m-C₃^2h; As well has been prepared the hitherto unknown Na₃GaO₃ a = 11.48, b = 10.82, c = 6.13 Å, space-group Imcm or I2cm Z = 8; and Cs₆[Ga₂O₆] a = 7.2₆, b = 12.1, c = 7.6₈ Å, ß = 105°, Z = 4, space-group P2₁/a.     

Oxydation intermetallischer Phasen: K4{Na2[Tl2O6]} aus NaTl und K2O2

Oxidation of Intermetallic Phases: K₄{Na₂[Tl₂O₆]} from NaTl and K₂O₂ The hitherto unknown K₄{Na₂[Tl₂O₆]} was prepared in form of transparent, yellow single crystals from NaTl and KO_1,08 (molar ratio 1:1.3; sealed Ag-cylinder; 450°C, 30 d). The structure determination (four-circle diffractometer, MoKα, 1 280 out of 1 523 I_o(hkl), R = 5.75%, R_w = 4.58%) confirms the space group P2₁/c with a = 641.3 pm, b = 691.1 pm, c = 1188.5 pm, β = 95.69° and Z = 2. As characteristic building units of the structure there are doubles of tetrahedra of [Tl₂O₆] and [Na₂O₆]. The compound is isotypic with Cs₆[In₂O₆] and Rb₆[Tl₂O₆]. The Madelung Part of Lattice Energy, MAPLE, the Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, and Charge Distribution, CHARDI, are calculated.     

Das erste Oxocobaltat des Typs A2CoIIO2: K2CoO2 = K4[OCoO2CoO]

The First Oxocobaltate of the Type A₂Co^IIO₂: K₂CoO₂ = K₄[OCoO₂CoO] By “reaction with the cylinder surface” of intimate mixtures of K₂O and CdO (molar ratio 1:1) in closed Co-Cylinders at 450°C during 73 d dark-red single-crystals of K₂CoO₂ were obtained. Structure solution and refinement (four-circle diffractometer-data, MoKα , 1 567 independent I_o(hkl), none was omitted, R = 3.25%, R_w = 2.67%) result in a monoclinic unit cell containing anions [Co₂O₄]^4? of two connected triangles similar to those of Rb₁₀[Co^IO₂]₂[CoO₄]. MAPLE-values and Charge-distributions are given and discussed.     

“Fragmentierung” und “Aggregation” bei Bleioxiden Über das Oligooxoplumbat(IV) K2Li6[Pb2O8]

“Fragmentation” and “Aggregation” on Lead Oxides. On the Oligooxoplumbate(IV) K₂Li₆[Pb₂O₈] For the first time, the dinuclear Oxoplumbate(IV) K₂Li₆[Pb₂O₈] has been prepared as transparent colourless single crystals by heating mixtures of K₂PbO₃, Li₂O, and “PbO₂” with K:Li:Pb = 1:3:1 e. g. [Ag-cylinders, sealed under vacuum in Supremax-glass ampoule, 660°C, 120 d]. The structure determination verifies the space group P1 with a = 6.9720(9), b = 5.9252(6), c = 5.9312(7) Å, α = 88.05(1)°, β = 107.94(1)°, γ = 107.30(1)°; d_x = 4.95 g · cm^?3, d_pyk = 4.91 g · cm^?3; Z = 1, [2107 symmetry independent hkl, fourcircle-diffractometer Philips PW 1100, ω—2Θ—scan, MoKα, R = 5.07%, R_w = 4.59%, absorption not considered]. The structure is characterized by the group [Pb₂O₈] — two edge connected (equatorial/apical) trigonal bipyramids — that is observed for the first time. Several ways of synthesis are given. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Neuartige Mäander mit Co3+ und Au3+: Na4[AuCoO5] = Na8 [(O2/2(CoO)O2AuO2/2)2]

Novel meander with Co³⁺ und Au³⁺: Na₄[AuCoO₅] = Na₈ ¹∞ [(O_2/2 (CoO)O₂AuO_2/2)₂] By “reaction with the wall” we obtained for the first time transparent brown single crystals of Na₄[AuCoO₅] while heating intimate mixtures of Co₃O₄, Na₂O₂, and K₂O₂ (Co: Na: K = 1.00:4.91:2.20; 650°C/44d) in a sealed gold-tube: monoclinic, P2₁/m, with a = 555.69(4) pm, b = 1042.11 (8) pm, c = 555.69(4) pm, β = 117.387(5)°, Z = 2. Characteristic features of Na₄[AuCoO₅] are meandric chains [(O_2/2 (CoO)O₂AuO_2/2)₂]. The structure has been determined by four-circle diffractometer data (Siemens AED 2; Mo? Kα , graphite, 881 I₀(hkl), R = 0.0366, R_w = 0.0316), parameters as given in the text. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, these via Mean Fictive Ionic Radii, and Charge-distribution, CHARDI, are calculated and discussed.     

Ein neues Oxouranat(VI): K2Li4[UO6]. Mit einer Bemerkung über Rb2Li4[UO6] und Cs2Li4UO6

A New Oxouranate(VI): K₂Li₄[UO₆]. With a Remark about Rb₂Li₄[UO₆] and Cs₂Li₄[UO₆] For the first time K₂Li₄UO₆ has been prepared by an exchange reaction of α-Li₆UO₆ with K₂O [K:U = 2.0:1, sealed au-tube; 750°C; 30 d single crystals; 680°C, 10 d powder]. The irregular shaped single crystals, which are of yellow color and sensitive to moisture crystallize in P3 m1 (Z = 1) with a = 619.27(5), c = 533.76(6) pm. The structure determination (PW 1100, AgKα R = 4.80%, R_w = 4.81% for 220 unique reflexions) reveals a new type of structure. The characteristic elements are the isolated group [UO₆] and the C.N. = 12 for K⁺. While Li(1) has a nearly regular square of 4 O^2? as coordination polyhedron, Li(2) is octahedrally surrounded. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed. In addition to K₂Li₄[UO₆] the new oxides Rb₂Li₄[UO₆] and Cs₂Li₄[UO₆] are prepared as pale yellow powders which are little sensitive to moisture (both: au-tube, 680°C, 10 d). According to powder datas both compounds are isotypic with K₂Li₄[UO₆] [Rb₂Li₄[UO₆]: a = 622.91(5), c = 535.93(6) pm; Cs₂Li₄[UO₆]: a = 626.70(6), c = 539.92(6) pm].     

Das erste gemischt-valente Oxocobaltat(I,II): Rb5Co2O4 [1]

A New Mixed-Valent Oxide of Cobalt(I, II): Rb₅Co₂O₄ For the first time we obtained a new mixed-valent oxide of mono- and divalent Cobalt. Black-red single-crystals of Rb₅Co₂O₄ were prepared by heating powders of “Rb₆CdO₄” in closed Co-cylinders at 500° during 48 days. Structure solution and refinement are covered by two measurements with four-circle diffractometers. MoKα : 2 145 I_o(hkl), out of 2 818 I_o(hkl), R = 9.85%, R_w = 5.93% AgKα : 1 813 I_o(hkl) out of 4 007 I_o(hkl), R = 9.46%, R_w = 6.51%) and confirm the space-group P1 . The lattice constants are a = 696.4(1) pm, b = 922.2(3) pm, c = 958.9(3) pm , α = 117.99(2)°, β = 89.96(2)°, γ h= 108.12(2)°, Z = 2 According to its composition Rb₁₀[OCoO]₂[OCoO₂CoO] the structure is built up by two Co atoms of chemically and crystallographically different nature. We find isolated dumb-bell-like anions [O? Co? O]^3? being already known with monovalent Co (e. g. K₃CoO₂) together with units [OCoO₂CoO]^4? of two connected triangles CoO₃ being well-known from K₂BeO₂ ? K₄[Be₂O₄]. ECoN/mEFIR calculations are made starting with values obtained by a new procedure called “MEFIR-FIT”.     

Über Oxoferrate mit „isolierten”︁ Anionen. Zur Kenntnis von Na8Fe2O7

On Oxoferrato with “isolated” Anions: Na₈Fe₂O₇ Na₈Fe₂O₇ has been prepared by heating of Na₂O and Fe₂O (Na:Fe = 4.6:1, sealed Ag-cylinders, 600°C, 7d) in from of yellow transparent single crystals [monoclinic, P2₁/c (No. 14); a = 8.70₃, b = 11.01₀, c = 10.09₆ Å, β = 107.6°; Z = 4; 4420 independent reflections, R = 0.063] which are isotypic with Na₈Ga₂O₇. The bonding angle Fe? O? Fe within an “isolated” group [Fe₂O₇] is extraordinary small (119.7°). Effective Coordination Numbers, ECoN (these by means of Mean Fictive Ionic Radii, MEFIR), and the Madelung Part of Lattice Energy, MAPLE, are calculated and discussed.     

Über „Lithovanadate”︁: Zur Kenntnis von Rb2[LiVO4] und Cs2[LiVO4]

On ?Lithovanadates”?: Rb₂[LiVO₄] and Cs₂[LiVO₄] By heating of well ground mixtures of the binary oxides [A₂O, Li₂O, V₂O₅, A : Li: V = 2.2 : 1.1 : 1.0 (A = Rb, Cs); Ni-tube, 750° 25 d] we obtained Rb₂[LiVO₄] and Cs₂[LiVO₄] colourless, orthorhombic single crystals. We found a new type of ?Lithovanadate”?-structure: space group Cmc2₁; a = 587.9(1), b = 1170.1(1), c = 793.3(1) pm, Z = 4 (A = Rb) bzw. a = 610.5(1), b = 1222.6(3), c = 815.5(2) pm, Z = 4 (A = Cs). The structure was determined by four-circle diffractometer data [MoKα -radiation; 997 from 1157 I₀(hkl), R = 7.75%, R_w = 5.54% (A = Rb); 686 from 686 I₀(hkl), R = 6.97%, R_w = 4.20% (A = Cs)] parameters see text. The Madelung part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Darstellung und Kristallstruktur von K6[Al2O6] und Rb6[Al2O6]

Preparation of Crystal Structure of K₆[Al₂O₆] and Rb₆[Al₂O₆] Colourless single crystals of K₆[Al₂O₆] have been prepared from intimate mixtures of KAlO₂ and K₂O (550°C, 90 d). The structure determination from four-circle diffractometer data (MoKα , 742 I_o(hkl), R = 2.2%, R_w = 2.1%) confirms the space group C2/m with Z = 2; a = 698.25 pm, b = 1 103.54 pm, c = 646.49 pm, β = 102.49°. Colourless single crystals of hitherto unknown Rb₆[Al₂O₆] have been prepared from intimate mixtures of RbAlO₂ and Rb₂O (520°C, 120 d). The structure determination from four-circle diffractometer data (MoKα , 1 240 I_o(hkl)) results in the residual values R = 7.2%, R_w = 4.9%; space group C2/m; a = 725.92 pm, b = 1 143.33 pm, c = 678.06 pm, β = 104.05°; Z = 2. K₆[Al₂O₆] and Rb₆[Al₂O₆] are isostructural with K₆[Fe₂O₆]. A characteristic structure unit is the anion [Al₂O₆]^6? consisting of two edge-sharing [AlO₄] tetrahedra. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are calculated and discussed.     

Über „Gemischt-Koordinierte”︁ einkernige Anionen. 2. Ein Oxoruthenat(VI) neuen Typs: CsK5Ru2O9 = CsK5[RuO5][RuO4]

On ?Mixed-coordinated”? isolated Anions. 2. A New Type of Oxoruthenates(VI): CsK₅Ru₂O₉ = CsK₅[RuO₅][RuO₄] By heating of intimate mixtures of the oxides [KO_1.1, CsO_1.2, RuO₂; K:Cs:Ru = 2.2:1:1; Ag-tube, 750°C, 34d] dark-green single crystals of CsK₅Ru₂O₉ = CsK₅[RuO₅][RuO₄] were obtained for the first time. Ru⁶⁺ shows two different polyhedra in this oxide (tetrahedron, trigonal bipyramid). Untill now Rb₆[TeO₅][TeO₄] [1] next to ?Mg₄GeO₆”? [3] and the isotypic high-pressure silicate [4] was the only examples known. The structure was determined by four-circle diffractometer data [Mo? Kα , 1824 from 1949 I₀(hkl), SG: Pnma, R equals; 12.6%, R_w = 4.5%], parameters see text. Guinier-Simon data gave a = 1701.6(3), b = 827.6(1), c = 905.7(1) pm, Z = 4. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, MEFIR, were calculated and discussed.     

Das erste oligomere Oxoferrat(III): K14[Fe4O13]

The First Tetraferrate(III): K₁₄[Fe₄O₁₃] For the first time K₁₄[Fe₄O₁₃] was obtained by annealing intimate mixtures of K₂O and LiFeO₂ (molar ratio 2.2:1) in closed Ni-cylinders (6 months, 610°C) in the form of yellow-brown single crystals. The structure determination (four circle diffractometer, MoKα, 3377 of 3377 I_o(hkl); R = 4,52%, R_w = 2,53%) confirms the space group P2₁/c; a = 677.9, b = 2956.2, c = 672,1 pm, β = 120.31°, Z = 2. Essential part of the structure are tetranuclear [Fe₄O₁₃]^14?-groups, oligomers consisting of four corner-sharing FeO₄-tetrahedra. Within the structure these groups are connected by two crystallographically distinct K-particles thus forming bands which are arranged according to a ?closest packing of bands”? interconnected by the rest of the K-particles. The structure is described via Schlegel-diagrams. It is isotypic with Na₁₄[Al₄O₁₃].