Neues über K2[MnF6], Rb2[MnF6] und Cs2[MnF6]

News on K₂[MnF₆], Rb₂[MnF₆], and Cs₂[MnF₆] Cs₂[MnF₆] (a = 8.97₂ Å) and Rb₂[MnF₆] (a = 8.53₁ Å) as well as this with K₂[MnF₆] (a = 8.22₁ Å and hexagonal a = 5.72₂, c = 9.33₁ Å) form mixed crystals of the K₂PtCl₆ type of structure. Calculations of the Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, lead contrary to former assumptions to distances Mn? F of about 1.86 Å (CN 6).     

Rubidiumhexaamidolanthanat und -neodymat,Rb3[La(NH2)6] und Rb3[Nd(NH2)6]; Strukturverwandtschaft zu K3[Cr(OH6)] und K4CdCl6

Rubidium Hexaamidolanthanate and -neodymate, Rb₃[La(NH₂)₆] and Rb₃[Nd(NH₂)₆]; Compounds. Structurally Related to K₃[Cr(OH)₆] and K₄CdCl₆ Colourless Rb₃[La(NH₂)₆] (a = 12.298(4) Å, c = 13.759(2) Å, N = 6, R3 c) and pale blue Rb₃[Nd(NH₂)₆] (a = 12.199(6) Å, c = 13.626(4) Å, N = 6, R32) have been prepared by the reaction of the corresponding metals (Rb: La resp. Nd = 3:1) with NH₃(P(NH₃) = 4–4.5 kbar) at 300°C. Single crystal x-ray methods gave their structures. It is shown by space group relations that these compounds are structurally related to one another and to further ternary amides as well as to K₃[Cr(OH)₆] and K₄CdCl₆.     

Zur Kenntnis der Hexafluororhodate(III): Über Cs2K[RhF6], Rb2K[RhF6], K2Na[RhF6], Rb2Na[RhF6] und Tl2Na[RhF6]

On the Knowledge of Hexafluororhodates(III): Cs₂K[RhF₆], Rb₂K[RhF₆], K₂Na[RhF₆], Rb₂Na[RhF₆] and Tl₂Na[RhF₆]. New prepared are the compounds Cs₂KRhF₆ (a = 9.04₉ Å), Rb₂NaRhF₆ (a = 8.49₂ Å), Rb₂KRhF₆ (a = 8.87₆ Å), K₂NaRhF₆ (a = 8.36₂ Å) and Tl₂NaRhF₆ (a = 8.52₆ Å), all cubic Elpasoliths of pink colour. The Madelung-Part of lattice energy, MAPLE, is calculated and discussed.     

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.     

Drei neue Selenoborato-closo-dodekaborate: Synthesen und Kristallstrukturen von Rb8[B12(BSe3)6], Rb4Hg2[B12(BSe3)6] und Cs4Hg2[B12(BSe3)6]

Three Novel Selenoborato- closo -dodecaborates: Syntheses and Crystal Structures of Rb₈[B₁₂(BSe₃)₆], Rb₄Hg₂[B₁₂(BSe₃)₆], and Cs₄Hg₂[B₁₂(BSe₃)₆] The three selenoborates Rb₈[B₁₂(BSe₃)₆] (P1, a = 10.512(5) Å, b = 10.450(3) Å, c = 10.946(4) Å, α = 104.53(3)°, β = 91.16(3)°, γ = 109.11(3)°, Z = 1), Cs₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.860(2) Å, b = 10.740(2) Å, c = 11.078(2) Å, α = 99.94(3)°, β = 90.81(3)°, γ = 115.97(3)°, Z = 1), and Rb₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.593(2) Å, b = 10.458(2) Å, c = 11.131(2) Å, α = 99.25(3)°, β = 91.16(3)°, γ = 116.30(3)°, Z = 1) were prepared from the metal selenides, amorphous boron and selenium by solid state reactions at 700 °C. These new chalcogenoborates contain B₁₂ icosahedra completely saturated with six trigonal-planar BSe₃ entities functioning as bidentate ligands to form a persubstituted closo-dodecaborate anion. The two isotypic compounds Rb₄Hg₂[B₁₂(BSe₃)₆] and Cs₄Hg₂[B₁₂(BSe₃)₆] are the first selenoborate structures containing a transition metal which are characterized by single crystal diffraction.     

Strukturchemische Verwandtschaft von Kaliumhexahydroxoscandat(III), K3[Sc(OH)6] mit den isotypen Hydroxometallaten Rb3[Sc(OH)6], K3[Cr(OH)6] und Rb3[Cr(OH)6]

Structural Relationship of Potassium Hexahydroxoscandate(III), K₃[Sc(OH)₆] with the Isotypic Hydroxometallates Rb₃[Sc(OH)₆], K₃[Cr(OH)₆], and Rb₃[Cr(OH)₆] Ternary hydroxides M}M^III(OH)₆{ with M^I ? K, Rb and M^III ? Sc, Cr were obtained in the same way as K₃[Cr(OH)₆] [1] from alkali metal amides and d-metal nitrates by a comproportionation reaction of amide and nitrate ions in supercritical ammonia to elementary nitrogen and hydroxide ions at 523 K and 3 ≤ p(NH₃) ≤ 6 kbar within 1 to 3 months. Their structures were determined by single crystal x-ray methods inclusive the positions of the hydrogen atoms. The ratio of size of r(M^I)/r(M^III) is related to the symmetry of these hydroxometallates. Structural relationships between K₃[Sc(OH)₆] and Rb₃[Sc(OH)₆], K₃(Cr(OH)₆], Rb₃[Cr(OH)₆]) and K₄[CdCl₆] [4] are discussed.     

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.     

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].     

Neue Oxocadmate der Alkalimetalle: K6[CdO4],Rb6[CdO4], Rb2CdO2 und Rb2Cd2O3

The crystal structure of K₆[CdO₄] and Rb₂CdO₂ has been determined from single crystal X-ray diffraction data and refined toR=0.058 (K₆[CdO₄]) andR=0.088 (Rb₂CdO₂). K₆[CdO₄] crystallizes hexagonal, space group P6₃mc with lattice constantsa=867.42 (6),c=665.5 (1) pm,c/a=0.767 andZ=2. It is isotypic with Na₆[ZnO₄]. Rb₂CdO₂ is orthorhombic, space group Pbcn witha=1045.0 (2),b=629.1 (1),c=618.3 (1) pm,Z=4, and crystallizes with the K₂CdO₂ structure type. The crystal structures can be deduced from the motif of a closest packed arrangement of O^2– with hexagonal (K₆[CdO₄]) or cubic (Rb₂CdO₂) stacking. The tetrahedra occupied by Cd²⁺ are isolated (K₆[CdO₄]) or edge-shared (formation of infinite SiS₂-like chains [CdO_4/2]) (Rb₂CdO₂). The powder diffraction pattern of Rb₆[CdO₄] [a=906.6 (1),c=694.3 (1) pm] and Rb₂Cd₂O₃ [a=642.6 (2),b=679.0 (1),c=667.9 (2) pm, =115.2 (1)] confirm isotypie with K₆[CdO₄] and K₂Cd₂O₃ respectively.

Herrn Prof. Dr.Gutman zum 65. Geburtstag gewidmet.     

K6[Mn2O6] und K6[Fe2 O6] - ein Vergleich

K₆[Mn₂O₆] and K₆[Fe₂O₆] - a Comparison K₆[Mn₂O₆] has been prepared (dark-red single crystals). The structure (a = 8.88₆, b = 6.76₀, c = 11.39₄ Å, γ = 132.1°, space group P2₁, Z = 2, 1151 symmetry independent reflections hk0–hk9, R = 0.051) shows Al₂Cl₆-like anions [Mn₂O₆]^6?. By unit-cell transformation to the monoclinic setting P2₁/a (a = 6.76₀, b = 11.39₄, c = 6.63₈ Å, β = 96,9°) the structural similarity to K₆[Fe₂O₆] becomes evident. The Madelung Part of Lattice Energy, MAPLE, is calculated.     

Chalkogenohalogenogallate(III) und -indate(III): Eine neue Verbindungsklasse in der dritten Hauptgruppe. Synthese und Struktur von [Ph4P]2[In2SX6], [Et4N]3[In3E3Cl6] · MeCN und [Et4N]3[Ga3S3Cl6] · THF (X = Cl,Br; E = S,Se)

Chalcogenohalogenogallates(III) and -indates(III): A New Class of Compounds for Elements of the Third Main Group. Preparation and Structure of [Ph₄P]₂[In₂SX₆], [Et₄N]₃[In₃E₃Cl₆] · MeCN and [Et₄N]₃[Ga₃S₃Cl₆] · THF (X = Cl, Br; E = S, Se) [In₂SCl₆]^2?, [In₂SBr₆]^2?, [In₃S₃Cl₆]^3?, [In₃Se₃Cl₆]^3?, and [Ga₃S₃Cl₆]^3? were synthesised as the first known chalcogenohalogeno anions of main group 3 elements. [Ph₄P]₂[In₂SCl₆] ( 1 ) (P1 ; a = 10.876(4) Å, b = 12.711(6) Å, c = 19.634(7) Å, α = 107.21(3)°, β = 96.80(3)°, γ = 109.78(3)°; Z = 2) and [Ph₄P]₂[In₂SBr₆] ( 2 ) (C2/c; a = 48.290(9) Å, b = 11.974(4) Å, c = 17.188(5) Å, β = 93.57(3)°, Z = 8) were prepared by reaction of InX₃, (CH₃)₃SiSSi(CH₃)₃ and Ph₄PX (X = Cl, Br) in acetonitrile. The reaction of MCl₃ (M = Ga, In) with Et₄NSH/Et₄NSeH in acetonitrile gave [Et₄N]₃[In₃S₃Cl₆] · MeCN ( 3 ) (P2₁/c; a = 17.328(4) Å, b = 12.694(3) Å, c = 21.409(4) Å, β = 112.18(1)°, Z = 4), [Et₄N]₃[In₃Se₃Cl₆] · MeCN ( 4 ) (P2₁/c; a = 17.460(4) Å, b = 12.816(2) Å, c = 21.513(4) Å, β = 112.16(2)°, Z = 4), and [Et₄N]₃[Ga₃S₃Cl₆] · THF ( 5 ) (P2₁/n; a = 11.967(3) Å, b = 23.404(9) Å, c = 16.260(3) Å, β = 90.75(2)°, Z = 4). The [In₂SX₆]^2? anions (X = Cl, Br) in 1 and 2 consist of two InSX₃ tetrahedra sharing a common sulfur atom. The frameworks of 3, 4 and 5 each contain a six-membered ring of alternating metal and chalcogen atoms. Two terminal chlorine atoms complete a distorted tetrahedral coordination sphere around each metal atom.     

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.     

Neues über TiF3 und Fluorotitanate(III) : Cs2K[TiF6], Rb2K[TiF6] und TiF3 Mit einer Bemerkung über Rb3[TiF6]

On TiF₃ and Hexafluorotitanates(III): Cs₂K[TiF₆] and Rb₂K[TiF₆], with a remark on Rb₃[TiF₆] By “redox-reaction with the wall” according to A₂B[CuF₆] + Ti = A₂B[TiF₆] + Cu we obtained for the first time single crystals of the Hexafluorotitanates(III). The violett irregular single crystals of Cs₂K[TiF₆] (a = 9.11₅ Å) and Rb₂K[TiF₆] (a = 8.91₀ Å) crystalise in accordance with the single-crystal studies as supposed in spcgrp. O-Fm3m No. 225. Dark blue crystals of TiF₃ crystalises in the VF₃-Typ. Parameters see text. TiF₃ (3.9–251.3 K) and Rb₃[TiF₆] (3.8–251.3 K) have been measured magnetically. The madelung part of lattice energy, MAPLE, and the effective coordination number, ECoN, via the mean fictive ionic radii, MEFIR, are calculated and discussed.     

Neue Oxocuprate (I). Über Cs3Cu5O4, Rb2KCu5O4, RbK2Cu5O4 und K3Cu5O4

New Oxocuprates(I). On Cs₃Cu₅O₄, Rb₂KCu₅O₄, RbK₂Cu₅O₄ and K₃Cu₅O₄ Cs₃Cu₅O₄ light yellow, powder as well as single crystals [a = 10.313(9), b = 7.630(1), c = 14.750(4) Å, β = 106.48(6)°], Rb₂KCu₅O₄ [a = 9.724(2), b = 7.443(0), c = 14.246(2) Å, β = 106.78(8)°], RbK₂Cu₅O₄ [a = 9.561(1), b = 7.411(0), c = 14.111(1) Å, β = 106.76(7)°] and K₃Cu₅O₄ [a = 9.422(1), b = 7.364(1), c = 13.995(2) Å, β = 107.00(2)°] are new prepared. The colour of the powders becomes lighter according to the sequence showed above. K₃Cu₅O₄ shows pale yellow. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

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.     

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].     

Ein Oxotellurat (VI) neuen Typs: Rb6[TeO5] [TeO4]

A New Type of Oxotellurates (VI): Rb₆[TeO₅] [TeO₄] For the first time single crystals of Rb₆Te₂O₉ was obtained by annealing intimate mixtures of the binary oxides (closed Ag-cylinder in supremax-glass ampoule, 680°C, 45 d). The structure elucidation (four-circle diffractometer, AgKα, 2083 I₀(hkl); R = 9.5%, R_w = 6.6%) confirms the space group C2/c with a = 1207.5(7), b = 1266.3(5), c = 1105.3(6) pm, β = 123.1(1)⁰, Z = 4 (Guinier-Simon photographs). Characteristic for this structure are ?isolated”? trigonal bipyramidal groups of [TeO₅] and ?isolated”? tetrahedral groups of [TeO₄], so we prefere to name the new compound Rb₆[TeO₅][TeO₄]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, the latter derived from Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.     

Chloro- und Polyselenoselenate(II) Darstellung,Struktur und Eigenschaften von [Ph3(C2H4OH)P]2[SeCl4] · MeCN, [Ph4P]2[Se2Cl6] und [Ph4P]2[Se(Se5)2]

Chloro- and Polyselenoselenates(II): Synthesis, Structure, and Properties of [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN, [Ph₄P]₂[Se₂Cl₆], and [Ph₄P]₂[Se(Se₅)₂] By symproportionation of elemental selenium and SeCl₄ in polar protic solvents the novel chloroselenates(+II), [SeCl₄]^2? and [Se₂Cl₆]^2?, could be stabilized; they were crystallized with voluminous organic cations. They were characterized from complete X-ray structure analysis. Yellow-orange [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN (space group P1 , a = 10.535(4), b = 12.204(5), c = 16.845(6) Å, α = 77.09(3)°, β = 76.40(3)°, γ = 82.75(3)° at 140 K) contains in its crystal structure monomeric [SeCl₄]^2? anions with square-planar coordination of Se(+II). The mean Se? Cl bond length is 2.441 Å. In yellow [Ph₄P]₂[Se₂Cl₆] (space group P1 , a = 10.269(3), b = 10.836(4), c = 10.872(3) Å, α = 80.26(3)°, β = 79.84(2)°, γ = 72.21(3)° at 140 K) a dinuclear centrosymmetric [Se₂Cl₆]^2? anion, also with square-planar coordinated Se(+II), is observed. The average terminal and bridging Se? Cl bond distances are 2.273 and 2.680 Å, respectively. From redox reactions of elemental Se with boranate/thiolate in ethanol/DMF the bis(pentaselenido)selenate(+II) anion [Se(Se₅)₂]^2? was prepared as a novel type of a mixed-valent chalcogenide. In dark-red-brown [Ph₄P]₂[Se(Se₅)₂] (space group P2₁/n, a = 12.748(4), b = 14.659(5), c = 14.036(5) Å, β = 108.53(3)° at 140 K) centrosymmetric molecular [Se(Se₅)₂]^2? anions with square-planar coordination of the central Se(+II) by two bidentate pentaselenide ligands is observed (mean Se? Se bond lengths: 2.658 Å at Se(+II), 2.322 Å in [Se₅]_2?). The resulting six-membered chelate rings with chair conformation are spirocyclically linked through the central Se(+II). The vibrational spectra of the new anions are reported.     

Tetrarubidium Nonagermanide(4–) Ethylenediamine,Rb4[Ge9][en]

Tetrarubidiumnonagermanid(4–)-ethylendiamin, Rb₄[Ge₉][en] Orange-farbene Kristalle von Rb₄[Ge₉][en] erhält man nach der Austauschreaktion einer Lösung von ,NaGe_2.25‘ (precursor) in Ethylendiamin (en) mit festem RbI bei 360 K und nachfolgender langsamer Abkühlung. Die Verbindung ist äußerst empfindlich gegen Oxidation und Hydrolyse. Der thermische Abbau im dynamischen Vakuum beginnt mit der vollständigen Abgabe von en bei 350 K. Es folgt die Sublimation von Rubidium in vier weiteren Stufen (Rb₈Ge₂₅, Rb₈Ge₄₄, Rb_xGe₁₃₆ mit x È 16, Ge). Das Ramanspektrum zeigt die charakteristischen Banden des Anions [Ge₉]^4– bei 151, 163, 185 und 222 cm^–1. Rb₄[Ge₉][en] kristallisiert in einem neuen Strukturtyp (Raumgruppe P2₁/m; a = 15.353 Å, b = 16.434 Å, c = 15.539 Å, β = 113.75°; Z = 6; Pearsonsymbol mP198-40), der als hierarchische Variante der Strukturen von Al₄YbMo₂ und CrB₄ (hierarchische Basistypen, „initiators”︁) beschrieben werden kann, indem Atome partiell durch Aggregate ersetzt werden: B₄[□][Cr] ≙ Al₄[Yb][Mo]₂ ≙ Rb₄[Ge₉][en]_1–2. Drei kristallographisch unabhängige [Ge₉]^4–-Cluster sind in ein vierbindiges 46⁵-Netz aus Rb-Atomen eingebettet, ein Netzwerk kondensierter Tetraasterane. Die Cluster sind verzerrte überkappte tetragonale Antiprismen mit D₁(Ge–Ge) = 2.57 Å (16 Ç ) und D₂(Ge–Ge) = 2.84 Å (4 Ç ). Die Atome der Cluster mit D₁ und D₂ liegen auf der Oberfläche eines Rotationsellipsoids (a = b = 2.136 Å, c = 2.431 Å). Die en-Moleküle befinden sich in offenen Kanälen entlang [1¯ 0 1]. Die Koordinationen [Ge₉]Rb_12/4 und Rb [Ge₉]_4/12 en_2/8 zeigen, daß beim ersten Schritt der Solvatisierung Kationen und Clusteranionen nicht voneinander getrennt werden.     

Die KristallStrukturen von K6[Ge2Te6] und K6[Sn2Te6] und ihre kristall-chemische Beziehung zum K6[Si2Te6]-Typ

Crystal Structures of K₆[Ge₂Te₆] and K₆[Sn₂Te₆] and their Relations to the K₆[Si₂Te₆] Type K₆[Ge₂Te₆] and K₆[Sn₂Te₆], the first members of the families of telluro-digermanates and telluro-distannates have been prepared and their structures determined. The space group is C 2/c with cell constants a = 16.010(8), b = 13.619(8), c = 9.713(5) Å, β = 95.19(5)° and Z = 4 for the Ge compound. The Sn compound has space group P 2₁/c, a = 9.590(5), b = 13.654(8), c = 9.606(5) Å, β = 116.84(5) and Z = 2. The structures were established by direct methods, using four-circle diffractometer data. The final R value for 828 (1677) independent reflexions is 0.068 (0.047) for the Ge (Sn) compound. Both structures have discrete X₂Te₆ groups (X = Ge, Sn) in staggered conformation connected by K atoms in distorted octahedral or trigonal prismatic environments and bear direct subgroup relationships to that of K₆[Si₂Te₆]. The average X? Te distance is 2.579 (2.724) Å and the X? X distance 2.492 (2.814) Å.