K4Au7Ge2: eine Gerüststruktur mit Au7-Doppeltetraedern und Ge2-Hanteln

K₄Au₇Ge₂: a Framework Structure with Au₇-Double-Tetrahedra and Ge₂-Dumb-Bells Black lustrous, brittle single crystals of a hitherto unknown K₄Au₇Ge₂ were synthesized by the reaction of KN₃, germanium- and gold-powder at 550°C. The structure was determined from X-ray single-crystal diffractometry data: space group R3 m, Z = 3, a = 6.411(3) Å, c = 27.912(20) Å, R/R_w(w = 1) = 0.046/0.056, Z(F ${}_{\text{º}}^{\text{2}}$ ) ≥ 3σ(F ${}_{\text{º}}^{\text{2}}$ ) = 302 and N(var.) = 18. K₄Au₇Ge₂ crystallizes in a substitution variant of the MgCu₂-type. Gold and germanium form a framework structure that consists of corner-sharing Au₇-double-tetrahedra and Ge₂-dumb-bells. The potassium atoms occupy channel-like cavities within the gold germanium partial structure.     

Syntheses and Crystal Structures of a New Niobium Polysulfide K6Nb4S22 and two New Dimorphic Tantalum Polysulfides K6Ta4S22

The new compounds K₆Nb₄S₂₂ and K₆Ta₄S₂₂ ( I ) have been synthesised by the reaction of NbS₂ or Ta metal in a K₂S₃ flux. Using TaS₂ as educt a second modification of K₆Ta₄S₂₂ ( II ) is obtained. K₆Nb₄S₂₂ and K₆Ta₄S₂₂ (form I ) crystallise in the monoclinic space group C2/c with a = 35.634 (2)Å, b = 7.8448 (4)Å, c = 12.1505 (5)Å, β = 100.853 (5)°, V = 3335.8 (3)ų, and Z = 4 for K₆Nb₄S₂₂ and a = 35.563 (7) Å, b = 7.836 (2)Å, c = 12.139 (2)Å, β = 100.56 (3)°, V = 3325.5 (2)ų, and Z = 4 for K₆Ta₄S₂₂ ( I ). The second modification K₆Ta₄S₂₂ (form II ) crystallises in the monoclinic space group P2₁/c with a = 7.5835 (6)Å, b = 8.7115 (5)Å, c = 24.421 (2)Å, β = 98.733 (9)°, V = 1594.6 (2)ų, and Z = 2. The structures consist of [M₄S₂₂]^6— anions composed of two M₂S₁₁ sub‐units which are linked into M₄S₂₂ units via terminal sulfur ligands. The anions are well separated by the K⁺ cations. Differences between the structures of the title compounds and those with the heavier alkali cations Rb⁺ and Cs⁺ are caused by the different arrangement of the [M₄S₂₂]^6— anions around the cations and the different S^2—/S₂^2— binding modes. The thermal behaviour of both modifications was investigated using differential scanning calorimetry (DSC). From these investigations there is no hint for a polymorphic transition between the two forms. After heating crystals of form II above the melting point and cooling the melt to room temperature a crystalline powder of form I can be isolated.     

Polychalcogenoaurates(I) with pseudo-onedimensional structures: Preparation and crystal structure of Cs2Au2Se3

Cs₂Au₂Se₃ was obtained as red platelike crystals by reacting a stoichiometric mixture of Cs₂Se, Au and Se at 670K. It crystallizes in space group C2/c, Z = 4 with a = 9.769(5) Å, b = 13.44(1) Å, c = 7.178(3) Å, β = 90.69(1)°. The crystal structure was determined from single crystal data and refined to a conventional R of 0.042 for 674 Fo's and 34 variables. The characteristic structural feature of this new selenoaurate is the formation of infinite helical anionic chains, _∞¹-[AuSeAuSe₂]²⁻ which run parallel to [001] and are separated by the alkali cations. The average Au-Se bond length is 2.402 Å, the bond length in the Se₂-unit is 2.436 Å. Au…Au contacts of 3.200 Å, are formed within the anionic chains. The cesium atoms are coordinated to seven Se in an irregular configuration.     

K4Au8Ga: eine Auffüllungsvariante des MgCu2‐Typs

K₄Au₈Ga: a Filling Variant of the MgCu₂ Type Black, brittle single crystals of K₄Au₈Ga were obtained as the main product of the reaction of potassium azide with gold sponge and gallium at T = 770 K. The structure of the compound (space group C2/m, Z = 4, a = 20.850(4) Å, b = 5.630(1) Å, c = 10.912(2) Å, β = 97,45(2)°) was determined from X‐ray single‐crystal diffractometry data. K₄Au₈Ga crystallizes in a filling variant of the MgCu₂ type. The gold atoms form a [Au_4/2]‐framework. One quarter of the tetrahedra is filled by gallium. The potassium atoms are placed in channel‐like cavities of the Au–Ga partial structure.     

Cs4Au7Sn2: eine Gold–Zinn-Gerüststruktur mit [Au7]-Clustern und Sn2-Hanteln

Cs₄Au₇Sn₂: a Gold Tin Framework Structure with Au₇ Clusters and Sn₂ Dumb-Bells Silver coloured, brittle single crystals of Cs₄Au₇Sn₂ were synthesized by reaction of caesium azide with gold sponge and tin powder at T = 920 K. The structure of the compound (space group R3m, Z = 3, a = 6.844(1) Å, c = 29.233(5) Å) was determined from X-ray single-crystal diffractometry data. Gold and tin form a framework structure that consists of interconnected [Au₇] clusters and Sn₂ dumb-bells. The caesium atoms accupy channel-like cavities within the gold tin partial structure.     

Verbindungen in den Systemen Kalium(Rubidium)/Gold/Antimon: K3Au3Sb2, Rb3Au3Sb2 und K1,74Rb0,26RbAu3Sb2

Compounds in the Systems Potassium(Rubidium)/Gold/Antimony: K₃Au₃Sb₂, Rb₃Au₃Sb₂, and K_1,74Rb_0,26RbAu₃Sb₂ Brittle, silver coloured single crystals of K₃Au₃Sb₂, Rb₃Au₃Sb₂ and K_1,74Rb_0,26RbAu₃Sb₂ were obtainded by reaction of the alkali metal azides (KN₃, RbN₃) with gold and antimon powder at 550°C. The structures of the isotypic compounds (R3 m, Z = 3) were determined by X-ray single-crystal diffractometer data: K₃Au₃Sb₂, a = 6,198(2) Å, c = 21,520(5) Å, R/R_w (w = 1) = 0,046/0,058, Z(F) ? 3σ(F) = 175, Z(Var.) = 14; Rb₃Au₃Sb₂, a = 6,443(3), c = 21,69(2), R/R_w (w = 1) = 0,059/0,082, Z(F) ? 3σ(F₀²) = 258, Z(Var.) = 14; K_1,74Rb_0,26RbAu₃Sb₂, a = 6,288(2) Å, c = 21,617(5) Å, R/R_w (w = 1) = 0,049/0,069, Z(F) ? 3σ(F) = 390, Z(Var) = 14. The compounds crystallize with the K₃Cu₃P₂-structure type. The Au? Sb partial structures consist of [AuSb_2/3] layers with linear Sb? Au? Sb dumb-bells and SbAu₃ pyramids. The layers are separated by two crystallographically independent alkali metal atoms along [001].     

Synthesis,Structural Characterization,and Cation Transport of Tripotassium Pentabismuth Arsenate K3Bi5(AsO4)6

During the exploration of the K₂O-Bi₂O ₃ -As₂O₅ system, single crystals of a new arsenate of trivalent bismuth, K₃Bi₅(AsO₄) ₆, were isolated by solid state reaction at 600°C. The title compound crystallizes in the monoclinic system, space group C2/c (N°15) with a = 18.257(2) Å, b = 7.260(1) Å, c = 20.130(4) Å, β = 119.86(1)°, and Z = 4. Its structure consists of a three-dimensional framework made up of AsO₄ tetrahedra and BiO₆ and BiO₇ polyhedra sharing edges and corners, delimiting cavities wherein K⁺ ions reside. This compound exhibits a potassium ion conductivity but with rather low conductivity value.     

Syntheses and Crystal Structures of the Cluster Compounds A2[(W6Br)Br] with A = K,Rb, Cs

K₂W₆Br₁₄ ( I ), Rb₂W₆Br₁₄ ( II ), and Cs₂W₆Br₁₄ ( III ) were formed by reactions of W₆Br₁₂ with the corresponding alkali metal bromides in evacuated silica tubes with a temperature gradient of 925 K/915 K. ( I ) crystallizes in the cubic space group Pn3 (no. 201), a = 13.808 Å, Z = 4, cP88. ( II ) crystallizes in the monoclinic space group C2/c (no. 15), a = 20.301 Å, b = 15.396 Å, c = 9.720 Å, β = 115.69°, Z = 4, mC88. ( III ) crystallizes in the trigonal space group P31c (no. 163), a = 10.180 Å, c = 15.125 Å, Z = 2, hP44. The crystal structures are composed of the isolated [(W₆Br)Br]^2– cluster anions and the alkali metal cations (d(W–W) = 2.635(2) Å, d(W–Brⁱ) = 2.624(4) Å, d(W–Br^a) = 2.595(4) Å). The shape of the anions is influenced by the crystal field symmetry, but the mean bond lengths are not changed by the cation size. The packing of the cluster anions corresponds to ccp pattern in ( I ) and hcp pattern in ( II ) and ( III ), respectively. The alkali metal cations in the octahedral holes are coordinated only by the Br^a ligands while those in the tetrahedral and trigonal-bipyramidal cavities are surrounded by Br^a and Brⁱ ligands. The details will be discussed and compared with other structures.     

Dimolybdenum Complexes Containing Pairs of Bridging Diphosphine and Carboxylate Ligands. Synthesis and Structures of trans-Mo2(O2CCH3)2(μ-dppa)2(BF4)2 and trans-Mo2X2(O2C(CH2)nCH3)2(μ-dppa)2 (n = 2, 10 or 12; X = Cl or Br; dppa = N,N-Bis(diphenylphosphino)amine)

The red complex trans-Mo₂(O₂CCH₃)₂(μ-dppa)₂(BF₄)₂, 1 , was prepared by reaction of [Mo₂(O₂CCH₃)₂(CH₃CN)₆][BF₄]₂ with dppa (dppa = Ph₂PN(H)PPh₂) in THF. The reactions of Mo₂(O₂C(CH₂)_nCH₃)₄ with dppa and (CH₃)₃SiX (X = Cl or Br) afforded the complexes trans-Mo₂X₂(O₂C(CH₂)_nCH₃)₂(μ-dppa)₂ (X = Cl, n = 2, 2; X = Br, n = 2, 3; X = Cl, n = 10, 4 ; X = Cl, n = 12, 5 ). Their UV-vis, IR and ³¹P{¹H}-NMR spectra have been recorded and the structures of 1, 2 and 3 have been determined. Crystal data for 1 : space group P2₁/n, a = 12.243(1) Å, b = 17.222(1) Å, c = 13.266(1) Å, β = 95.529(1)°, V = 2784.1(6) ų, Z = 2, with final residuals R = 0.0509 and Rw = 0.0582. Crystal data for 24CH₃Cl₂: space group P2₁/n, a = 13.438(1) Å, b = 19.276(1) Å, c = 14.182(1) Å, β = 111.464(1)°, V = 3418.9(6) ų, Z = 2, with final residuals R = 0.0492 and Rw = 0.0695. Crystal data for 3·4CH₂Cl₂: space group P2₁/n, a= 13.579(1) Å, b = 19.425(1) Å, c = 14.199(1) Å, β = 111.881(2)°, V = 3475.6(7) ų, Z = 2, with final residuals R = 0.0703 and Rw = 0.0851. Comparison of the structural data shows that the effect of the axial ligand on weakening the Mo-Mo bond strength is X^? > CH₃CN > BF₄^?. The T_m values are 121.7 °C for 2 , 111.1 °C for 3 and 91.5 °C for 5 , respectively.     

One‐dimensionally linked Chain Crown Ether Complexes. Syntheses and Crystal Structures of Complexes [K(18‐Crown‐6)]2[M(SeCN)4](H2O) (M = Pd,Pt)

18‐crown‐6(18‐C‐6) complexes with K₂[M(SeCN)₄] (M = Pd, Pt): [K(18‐C‐6)]₂[Pd(SeCN)₄] (H₂O) ( 1 ) and [K(18‐C‐6)]₂[Pt(SeCN)₄](H₂O) ( 2 ) have been isolated and characterized by elemental analysis, IR spectroscopy and single crystal X‐ray analysis. The complexes crystallize in the monoclinic space group P2₁/n with cell dimensions: 1 : a = 1.1159(3) Å, b = 1.2397(3) Å, c = 1.6003(4) Å, β = 92.798(4)°, V = 2.2111(8) ų, Z = 2, F(000) = 1140, R₁ = 0.0418, wR₂ = 0.0932 and 2 : a = 1.1167(3) Å, b = 1.2394(3) Å, c = 1.5968(4) Å, β = 92.945(4)°, V = 2.2071(9) ų, Z = 2, F(000) = 1204, R₁ = 0.0341, wR₂ = 0.0745. Both complexes form one‐dimensionally linked chains of [K(18‐C‐6)]⁺ cations and [M(SeCN)₄]^2— (M = Pd, Pt) anions bridged by K‐O‐K interactions between adjacent [K(18‐C‐6)]⁺ units.     

The Crystal Structure of Binuclear Metal Complexes of 7-Azaindole: Cu2 (CH3CO2)2 (C7H5N2)2(C7H6N2)2 AND Ni2(C7H5N2)4.2DMF

The crystal and molecular structures have been determined by single-crystal X-ray methods for the binuclear metal ions (II) complexes of 7-azaindole (1H-pyrrolo [2,3-b] pyridine, C₇H₆N₂ denoted by HL), Cu₂(CH₃CO₂)₂.·L₂(HL)₂ and Ni₂L₄.2DMF. The dark green crystal of Cu₂(CH₃CO₂)₂L₂(HL)₂ was found to crystallize in the monoclinic space group P 2₁/n with a = 9.566(2), b = 12.752(2), c = 12.852(4) Å, β = 99.23(3)⁰, V = 1547 Å, Z = 2, the final R = 0.062 and Rw = 0.053 for 1488 observations from 2722 unique reflections. The Cu-Cu distance is 2.747(2), Cu-N (L^?, bridge) is 1.966(7), Cu-N (HL, axial) is 2.229(8), and Cu-O is 2.031(6)Å. The red crystal of Ni₂L₄.2DMF was was found to crystallize in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm P \bar 1} $$\end{document} with a = 8.907(5), b = 9.462(2), c = 10.217(2) Å, α = 90.48(2), β = 91.09(3), γ = 110.69(3)⁰, V =805 ų, Z = 1, the final R = 0.063 and Rw = 0.069 for 1489 observations from 2834 unique reflections. The Ni-Ni distance is 2.594(2), Ni-N is 1.905(7) Å. These two molecules lie on crystllographic inversion centers and exhibit ligand disorder.     

Die Tetracyanoborate M[B(CN)4], M = [Bu4N]+, Ag+, K+

The Tetracyanoborates M[B(CN)₄], M = [Bu₄N]⁺, Ag⁺, K⁺ The tetracyanoborate anion is prepared for the first time as the tetrabutylammonium salt by the reaction of [NBu₄]BX and BX₃ (X = Br, Cl) in toluene with KCN. After purification and recrystallization of the product from CHCl₃ colorless and needle size single crystals of [Bu₄N][B(CN)₄] are formed. After metathesis with AgNO₃ the silver salt and subsequently with KBr the potassium salt is prepared. The three salts are characterized by single crystal X‐ray diffraction (Ag[B(CN)₄] P 43m, a = 5.732(1) Å, V = 188.3 ų, Z = 1, R₁ = 0.75%; K[B(CN)₄] I4₁/a, a = 6.976(1), c = 14.210(3) Å, V = 691.5 ų, Z = 4, R₁ = 1.90%; [Bu₄N][B(CN)₄] Pnna, a = 17.765(3), b = 11.650(2), c = 11.454(2) Å, V = 2370.5 ų, Z = 4, R₁ = 6.09%) and by NMR‐, IR‐, Raman‐ as well by UV‐spectroscopy.     

Primitive cubic packing of anions in Cs4[Re6Te8(CN)6]· 2H2O and Ba2[Re6Te8(CN)6] · 12H2O crystals

Crystal structures of Cs₄[Re₆Te₈(CN)₆]·2H₂O (1) and Ba₂[Re₆Te₈(CN)₆]· 12H₂O (2) are determined. Crystals 1 are orthorhombic, a = 14,282(1), b = 12.910(1), c = 18.040(1) Å, V_cell = 3326.3(8) ų, space group Pbcn, Z = 4, d_calc = 5.715 g/cm³, R(F) = 0.0482 for 3193 F_hkl > 4σ(F). Crystals 2 are triclinic, a = 9.671(3), b = 9.697(4), c = 11.039(4) Å, α = 89.86(3), β = 72.34(3), γ = 82.46(3)°, V_cell = 977.2(6) ų, space group P1, Z = 1, d^calc = 4.733 g/cm³, R(F) = 0.0490 for 3226 F_hkl > 4σ(F). In both structures, the [Re₆Te₈(CN)₆]^4? anions form a distorted primitive cubic packing with distances between the centers 9.02-9.63 Å in 1 and 9.70-11.04 Å in 2. The Cs⁺ cations in 1 lie near the face centers of the cubes formed by the onions. In 2, cation pairs (Ba²⁺)₂ bonded to two solvate water molecules are formed; the pairs lie at the centers of the anion cubes. In structures 1 and 2, there are shortened contacts between the tellurium atoms belonging to the neighboring anions (3.75-4.09 and 3.95-4.22 Å, respectively).     

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.     

One‐Dimensional Zinc Selenophosphates: A2ZnP2Se6 (A = K,Rb, Cs)

The new compounds A₂ZnP₂Se₆ (A = K, Rb, Cs) were synthesized via molten salt flux syntheses. The crystals feature one‐dimensional ¹/_∞[ZnP₂Se₆]^2– chains charge balanced by alkali metal ions between the chains. K₂ZnP₂Se₆ crystallizes in the monoclinic space group P2₁/c; cell parameters a = 12.537(3) Å, b = 7.2742(14) Å, c = 14.164(3) Å, β = 109.63(3)°, Z = 4, and V = 1216.7(4) ų. Rb₂ZnP₂Se₆ and Cs₂ZnP₂Se₆ are isotypic, crystallizing in the triclinic space group P$\bar{1}$ . Rb₂ZnP₂Se₆ has cell parameters of a = 7.4944(15) Å, b = 7.6013(15) Å, c = 12.729(3) Å, α = 96.57(3)°, β = 105.52(3)°, γ = 110.54(3)°, Z = 2, and V = 636.6(2) ų. Cs₂ZnP₂Se₆ has cell parameters of a = 7.6543(6) Å, b = 7.7006(6) Å, c = 12.7373(11) Å, α = 97.007(7)°, β = 104.335(7)°, γ = 109.241(6)°, Z = 2, and V = 669.54(10) ų.     

Preparation of Aluminum Alkoxides and Crystal Structures of [Al{(S)-(-)-μ-OC(H)(CH3)C(Ph)2OH}Cl2]2·2Et2O and [(μ-O(CH2)2OPh)AlMe2]2

The reaction of (S)-(-)-1, l-diphenyl-propane-1,2-diol with AlCl₃ in diethyl ether furnishes the product [Al((S)-(-)-μ₂-OC(H)(Me)C(Ph)₂OH)Cl₂]₂ 1, which decomposes slowly above 25 °C. Complex 1·2Et₂O Crystallizes in the non-centrosymmetric monoclinic space group P2₁ with a=10.591(1) Å, b=16.718(1) Å, c = 12.156(2) Å, β=99.30(2)°, V = 2124.1(3) Å₃, z = 4, R = 4.67%, Rw=4.84%, GoF=1.14. The structure of 1 shows a dimer feature, which is hydrogen bonded to two diethyl ether molecules. In the reaction of 2-phenoxyethanol with AlMe₃, the dimeric [(μ-O(CH₂)₂OPh)AlMe₂]₂ is obtained in high yield. 2 crystallizes in the monoclinic space group P2₁/c with a = 7.398(2) Å, b = 7.376(2) Å, c = 20.710(2) Å, β = 90.56(2)°, v = 1129.9(4) ų, z=4, R=5.70%, Rw=7.15%, GoF=1.59.     

Syntheses,Structures and Spectroscopic Studies of Dimolybdenum Complexes Containing Bridging Butyrate and Phosphine Ligands

By reactions of Mo₂(O₂CPrⁿ)X₂(PPh₃)₂ (X = Cl, 1 ; X = Br, 2 ) with Ph₂PCH₂CH₂P(Ph)CH₂CH₂PPh₂ (etp) in CH₂X₂, the quadruply bonded complexes containing bridging butyrate and tridentate phosphine ligands of the type Mo₂(O₂CPrⁿ)X₃(η³‐etp) (X = Cl, 3 ; X = Br, 4 ) were prepared. Their UV‐vis and³¹P{¹H}‐NMR spectra have been recorded and the structures of 1 and 2 have been determined by X‐ray crystallography. Crystal data for 1 : space group P2₁/c, a = 9.708 (2)Å, b = 18.491 (4)Å, c= 12.688 (3)Å, β = 110.76 (3)°, V = 2130 ų, Z = 2, with final residuals R = 0.0441 and Rw = 0.0519. Crystal data for 2 : space group P2₁/c, a = 9.737 (1)Å, b = 18.632(1)Å, c = 12.680(1)Å, β= 110.27 (1)°,V = 2158.2 (3) ų, Z = 2, with final residuals R = 0.0322 and Rw = 0.0481. The δ → δ* transition energies, ³¹P{¹H}‐NMR chemical shifts and the coupling constants are dependent on the natures of the halogen atoms and the carboxylate ligands. The through metal‐metal couplings |³J_{P‐Mo‐Mo‐P}| for complexes of the type Mo₂(O₂CR)X₃(η³‐P₃), which contain η³‐polydentate phosphine ligands are about 20 ± 2 Hz.     

Synthesis,Crystal Structure and Magnetic Property of Diiron Complex [Fe(phen)3][Fe2OCl6]·2CH3CN

A new diiron complex has been synthesized and characterized by X‐ray single crystal structural analysis: [Fe^II(phen)₃][Fe^III₂OCl₆]·2CH₃CN. The complex crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 21.162(4) Å, b = 15.168(3) Å, c = 14.812(3) Å, β= 112.71 (3)°, V = 4385.8(15) ų, Dx = 1.543 Mg/m³, Z = 4. The corresponding variable temperature susceptibility measurement shows that there exists an antiferromagnetic interaction in the complex.     

Na2B2Se7, K2B2S7 und K2B2Se7: Drei Perchalkogenoborate mit neuem polymeren Anionengerüst

Na₂B₂Se₇, K₂B₂S₇, and K₂B₂Se₇: Three Perchalcogenoborates with a Novel Polymeric Anion Network Na₂B₂Se₇ (I 2/a; a = 11.863(4) Å, b = 6.703(2) Å, c = 13.811(6) Å, β = 109.41(2)°; Z = 4), K₂B₂S₇ (I 2/a; a = 11.660(2) Å, β = 6.827(1) Å, c = 12.992(3) Å, β = 106.78(3)°; Z = 4), and K₂B₂Se₇ (I 2/a; a = 12.092(4) Å, b = 7.054(2) Å, c = 13.991(5) Å, β = 107.79(3)°; Z = 4) were prepared by reaction of stoichiometric amounts of sodium selenide (potassium sulfide) with boron and sulfur or of potassium selenide and boron diselenide, respectively, at 600°C with subsequent annealing. The crystal structures consist of polymeric anion chains of composition ([B₂S₇]^2?)_n or ([B₂Se₇]^2?)_n formed by spirocyclically connected five-membered B₂S₃ (B₂Se₃) rings and six-membered B₂S₄ (B₂Se₄) rings. The nine-coordinate alkaline metal cations are situated in between.