Preparation,Crystal Structure and Vibrational Spectra of Ca2P2O6·2H2O and [Ca(H2O)3(H2P2O6)]·0.5(C12H24O6)·H2O

The calcium salts Ca₂P₂O₆ · 2H₂O ( 1 ) and [Ca(H₂O)₃(H₂P₂O₆)] · 0.5(C₁₂H₂₄O₆) · H₂O ( 2 ) were prepared and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pbca and compound 2 in the monoclinic space group P2₁/n. The crystal structure of compound 1 consists of chains of edge‐sharing [CaO₇] polyhedra linked by hypodiphosphate(IV) anions to form a three‐dimensional network. The crystal structure of compound 2 consists of alternated layers of crown ether and water molecules and respective ionic units. Within the layers of ionic units the Ca²⁺ cations are octahedrally coordinated by three monodentate dihydrogenhypodiphosphate(IV) anions and three water molecules. The IR/Raman spectra of the title compounds were recorded and interpreted, especially with respect to the [P₂O₆]^4– and [H₂P₂O₆]^2– groups. The phase purity of 2 was verified by powder diffraction measurements.     

Carbonat‐Hydrate der schweren Alkalimetalle: Darstellung und Struktur von Rb2CO3 · 1,5 H2O und Cs2CO3 · 3 H2O

Carbonate Hydrates of the Heavy Alkali Metals: Preparation and Structure of Rb₂CO₃ · 1.5 H₂O und Cs₂CO₃ · 3 H₂O Rb₂CO₃ · 1.5 H₂O and Cs₂CO₃ · 3 H₂O were prepared from aqueous solution and by means of the reaction of dialkylcarbonates with RbOH and CsOH resp. in hydrous alcoholes. Based on four‐circle diffractometer data, the crystal structures were determined (Rb₂CO₃ · 1.5 H₂O: C2/c (no. 15), Z = 8, a = 1237.7(2) pm, b = 1385.94(7) pm, c = 747.7(4) pm, β = 120.133(8)°, V_EZ = 1109.3(6) · 10⁶ pm³; Cs₂CO₃ · 3 H₂O: P2/c (no. 13), Z = 2, a = 654.5(2) pm, b = 679.06(6) pm, c = 886.4(2) pm, β = 90.708(14)°, V_EZ = 393.9(2) · 10⁶ pm³). Rb₂CO₃ · 1.5 H₂O is isostructural with K₂CO₃ · 1.5 H₂O. In case of Cs₂CO₃ · 3 H₂O no comparable structure is known. Both structures show [(CO₃^2–)(H₂O)]‐chains, being connected via additional H₂O forming columns (Rb₂CO₃ · 1.5 H₂O) and layers (Cs₂CO₃ · 3 H₂O), respectively.     

Preparation,Crystal Structure,Vibrational Spectra,and Thermal Behavior of Tl2H2P2O6 and Tl4P2O6

The new thallium(I) salts, Tl₂H₂P₂O₆ ( 1 ) and Tl₄P₂O₆ ( 2 ), were prepared and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 crystallizes in the monoclinic space group P2₁/c and compound 2 in the orthorhombic space group Pbca. Both structures feature channels occupied by the lone electron pairs of Tl⁺ cations. Furthermore, those are built up by discrete [H₂P₂O₆]^2– for compound 1 and [P₂O₆]^4– units for 2 in staggered conformation for the P₂O₆ skeleton and the thallium cations. In Tl₂H₂P₂O₆ ( 1 ) the hydrogen atoms of the [H₂P₂O₆]^2– ion are in a “trans‐trans” conformation. The O ··· H–O hydrogen bonds between the [H₂P₂O₆]^2– groups consolidate the structure 1 into a three‐dimensional network. FT‐IR/FIR and FT‐Raman spectra of the crystalline title compounds were recorded and a complete assignment for the P₂O₆^4– modes is proposed. The phase purity of 1 was verified by powder diffraction measurements.     

Earth Alkaline Tetrathiosquarates: Syntheses and Crystal Structures of MgC4S4 · 6 H2O and CaC4S4 · 4 H2O

Concentrated aqueous solutions of magnesium chloride and calcium nitrate, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄ · H₂O, the isolation of the earth alkaline salts MgC₄S₄ · 6 H₂O ( 1 ) and CaC₄S₄ · 4 H₂O ( 2 ) as orange and red crystals. The crystal structure determinations ( 1 : monoclinic, C2/c, a = 17.2280(7), b = 5.9185(2), c = 13.1480(4) Å, β = 104.730(3)°, Z = 4; 2 : monoclinic, P2₁/m, a = 7.8515(3), b = 12.7705(5), c = 10.6010(4) Å, β = 93.228(2)°, Z = 4) show the presence of C₄S₄^2? ions with almost undistorted D_4h symmetry having average C–C and C–S bond lengths of 1.451Å and 1.659Å for 1 and 1.451Å and 1.655Å for 2 . The structure of 1 contains discrete, octahedral [Mg(H₂O)₆]²⁺ complexes. Several O–H····O and O–H····S bridges with H····O and H····S distances of less than 2.50Å connect cations and anions. The structure of 2 is built of concatenated, edge‐sharing Ca(H₂O)₆S₂ polyhedra. The Ca²⁺ ions have the coordination number eight, C₄S₄^2? act as a chelating ligands towards Ca²⁺ with Ca–S distances of 3.14Å. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Darstellung und Kristallstrukturen der ersten Alkalimetall‐hexacarbonatooxotetraberyllate: K6[Be4O(CO3)6] · 7 H2O und K6[Be4O(CO3)6]

Preparation and Crystal Structures of the first Alkalimetall‐hexacarbonato‐oxotetraberyllates: K₆[Be₄O(CO₃)₆] · 7 H₂O and K₆[Be₄O(CO₃)₆] K₆[Be₄O(CO₃)₆] · 7 H₂O has been prepared by dissolving freshly precipitated Be(OH)₂ in an aqueous KHCO₃ solution. After enriching the title compound by extraction with ethanol the heptahydrate crystallizes from the organic phase (triklin, P1¯ (No. 2) with a = 951, 01(11), b = 958, 45(12), c = 1601, 7(2) pm, α = 79, 253(13)°, β = 78, 943(12)°, γ = 65, 119(12)°, V_EZ = 1290, 6(3)·10⁶ pm³, Z = 2). Thermal decomposition forms rhombohedral crystals of the anhydrous compound (trigonal‐rhombohedric, R3¯ (No. 148) with a = 1416, 42(6), c = 1704, 5(1) pm, V_EZ = 2961, 4(3)·10⁶ pm³, Z = 6).     

Synthesis,Crystal Structure,Vibrational Spectra,and Thermal Behaviour of [Ph4P]2[Bi2(μ‐Br)2Br6 (CH3COCH3)2]

[Ph₄P]₂[Bi₂Br₈(CH₃COCH₃)₂] ( 1 ) was obtained by the reaction of [Ph₄P]Br and BiBr₃ in acetone. Single crystals were grown by allowing a layer of n‐hexane to diffuse into the acetonic solution of 1 . The crystal structure was determined by means of X‐ray diffraction. 1 crystallises with monoclinic symmetry in the space group P2₁/n, No. 14 with the lattice parameters: a = 13.358(2), b = 12.637(2), c = 18.565(3) Å, β = 102.62(1)°, V = 3058.1(8) ų and Z = 4. The structure is characterised by the anion [Bi₂Br₈(CH₃COCH₃)₂]^2– which is embedded in a matrix of [Ph₄P]⁺ cations. The anion can be described as two edge‐sharing square pyramids with the apical bromide ions in anti‐position. Acetone co‐ordinates the bismuth atoms via oxygen atoms and increases the co‐ordination number of central bismuth atoms to six which results in the formation of a distorted bi‐octahedron. The distortion is due to the difference in terminal and bridging Bi–Br bond lengths. FT‐IR and Raman spectroscopic data are presented. In addition, the thermal behaviour of the compound was studied with the aid of TG/DSC coupled with MS revealing that acetone leaves the crystal in two steps. The compound melts at 203 °C and transforms into a glass on cooling.     

The Phase Diagram of the System [Ph4P]Br/BiBr3. Synthesis,Crystal Structure,Thermal Behaviour,and Vibrational Spectra of [Ph4P]3[Bi2Br9] · CH3COCH3 and two Modifications of [Ph4P]4[Bi6Br22]

The phase diagram of the system [Ph₄P]Br/BiBr₃ was investigated with the aid of DSC, TG and temperature dependent X‐ray powder diffraction measurements. By varying the reaction conditions, stoichiometry and crystallisation conditions of the reaction between BiBr₃ and [Ph₄P]Br four polynuclear bromobismuthates are formed. We report here the crystal structure of the solvation product [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃, which crystallises with monoclinic symmetry in the S. G. P2₁/n No. 14, a = 12.341(1), b = 32.005(3), c = 19.929(3) Å, β = 99.75(2)°, V = 7758(7) ų, Z = 4 and the crystal structures of two modifications of the compound [Ph₄P]₄[Bi₆Br₂₂]. The α‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.507(4) Å, b = 14.434(4) Å, c = 17.709(5) Å, α = 81.34(2)°, β = 72.42(2)°, γ = 72.53(2)°, V = 3132.7(1) ų, Z = 2. The high‐temperature β‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.893(4) Å, b = 14.267(3) Å, c = 16.580(3), α = 100.13(2)°, β = 96.56(2)°, γ = 110.01(2)°, V = 2985.5(1) ų, Z = 2. Lattice parameters of [Ph₄P]₄[Bi₈Br₂₈] are also given. The thermal behaviour of the compounds and in addition the vibrational spectra of [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃ are presented and discussed.     

Earth Alkaline Tetrathiosquarates. II. – Syntheses and Crystal Structures of SrC4S4·4 H2O and Ba4K2(C4S4)5·16 H2O

Concentrated aqueous solutions of strontium chloride and barium chloride, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄·H₂O, the isolation of the earth alkaline salts SrC₄S₄·4 H₂O ( 1 ) and Ba₄K₂(C₄S₄)₅·16 H₂O ( 2 ), both as dark red crystals. The crystal structure determinations ( 1 : orthorhombic, Pnma, a = 8.149(1), b = 12.907(2), c = 10.790(2) Å, Z = 4; 2 : orthorhombic, Pbca, a = 15.875(3), b = 21.325(5), c = 16.119(1) Å, Z = 4) show the presence of C₄S₄²⁻ ions with only slightly distorted D_4h symmetry having average C–C and C–S bond lengths of 1.41Å and 1.681Å for 1 and 1.450Å and 1.657Å for 2 . The structure of 1 contains concatenated edge‐sharing Sr(H₂O)₆S₂ polyhedra. The Sr²⁺ ions are in eight‐fold coordination with Sr–O distances of 2.50–2.72Å and Sr–S distances of 3.21Å, (C₄S₄)²⁻ acts as a chelating ligand towards Sr²⁺. The structure is closely related to the previously reported Ca²⁺ containing analogue, which is of lower symmetry belonging to the monoclinic crystal system. A supergroup‐subgroup relation between the space groups of both structures is present. The structure of 2 is made up of Ba²⁺ and K⁺ ions in eight and nine‐fold coordination by H₂O molecules and (C₄S₄)²⁻ ions which act as chelating ligands towards one cation and bridging between two cations. The coordination polyhedra of the cations are connected by common edges and corners in two dimensions to layers which are connected by tetrathiosquarate ions to a three‐dimensional network. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Synthesis,Crystal Structures,and Vibrational Spectra of Novel Azidopalladates of the Alkali Metals Cs2[Pd(N3)4] and Rb2[Pd(N3)4]·2/3H2O

The transparent dark orange compounds Cs₂[Pd(N₃)₄] and Rb₂[Pd(N₃)₄]·²/₃H₂O are synthesized by reaction of the respective binary alkali metal azides with K₂PdCl₄ in aqueous solutions. According to single‐crystal X‐ray diffraction investigations, the novel ternary azidopalladates(II) crystallize in the monoclinic space group P2₁/c (no. 14) with a = 705.7(2) pm, b = 717.3(2) pm, c = 1125.2(5) pm, β = 104.58(2)°, mP30 for Cs₂[Pd(N₃)₄] and a = 1041.4(1) pm, b = 1292.9(2) pm, c = 1198.7(1) pm, β = 91.93(1)°, mP102 for Rb₂[Pd(N₃)₄]·²/₃H₂O, respectively. Predominant structural features of both compounds are discrete [Pd^II(N₃)₄]^2– anions with palladium in a planar coordination by nitrogen, but differing in point group symmetries., The vibrational spectra of the compounds are analyzed based on the idealized point group C_4h of the spectroscopically relevant unit, [Pd(N₃)₄]^2– taking into account the site symmetry splitting due to the symmetry reduction in the solid phase.     

Crystal Structure and Vibrational Spectrum of Dipotassium Manganese(II) Hexathiodiphosphate(IV), K2Mn[P2S6]

K₂Mn[P₂S₆] was synthesized from the elements in sealed quartz ampoules at 1 173 K. The compound forms transparent light brown crystals, stable against air and moisture. The crystal structure (monoclinic; space group P2₁/n, No. 14; a = 6.1966(9), b = 12.133(2), c = 7.424(1) Å, β = 101.52(1)°, Z = 2; Pearson code mP22) consists of columns of face-sharing S₆ polyhedra (distorted octahedra and trigonal antiprisms) parallel to the a axis, interconnected by inserted K⁺ (CN 10; d(K? S) = 3.23–3.92 Å). The S₆ polyhedra of the columns are centered alternately by Mn (in octahedra with d?(Mn? S) = 2.647 Å) and P₂ pairs (in trigonal antiprisms) which are inclined to the a axis by 73.1°. The bond lengths in the resulting hexathiodiphosphate(IV) anions, [P₂S₆]^4?, with approximate 3 2/m–D_3d symmetry, are d(P? P) = 2.211 Å and d(P? S) = 2.018 Å. K₂Mn[P₂S₆] is isotypic to K₂Fe[P₂S₆], being the second member of this structure type. The internal modes of the observed Raman and FIR/IR spectra of K₂Mn[P₂S₆] are in accord with the factor group analysis, and the fundamentals are assigned on the basis of [P₂S₆]^4? units, taking into account the deviation of the D_3d symmetry.     

Syntheses and Crystal Structures of the Cyclotriphosphate Hydrates Nd(P3O9)·3H2O,Nd(P3O9)·4.5H2O,RE(P3O9)·5H2O (RE = Pr,Nd), and Na3RE(P3O9)2·6H2O (RE = Pr,Nd)

Several rare‐earth cyclotriphosphate hydrates were obtained from mixtures of sodium cyclotriphosphates and the respective rare‐earth chlorides. Nd(P₃O₉) · 3H₂O [P$\bar{6}$ , Z = 3, a = 677.90(9), c = 608.67(9) pm, R₁ = 0.016, wR₂ = 0.038, 312 data, 36 parameters] was obtained by a solid state reaction and is isotypic with respective rare‐earth phosphate hydrates, while all the others adopt new structure types. Nd(P₃O₉) · 4.5H₂O [C2/c, Z = 8, a = 1644.6(3), b = 756.11(15), c = 1856.1(4) pm, β = 97.25(3)°, R₁ = 0.032, wR₂ = 0.081, 1763 data, 194 parameters], Nd(P₃O₉) · 5H₂O [P2₁/c, Z = 4, a = 773.75(15), b = 1149.1(2), c = 1394.9(3) pm, β = 106.07(3)°, R₁ = 0.042, wR₂ = 0.082, 1338 data, 194 parameters], Pr(P₃O₉) · 5H₂O [P$\bar{1}$ , Z = 2, a = 745.64(15), b = 889.07(18), c = 934.55(19) pm, α = 79.00(3), β = 80.25(3), γ = 66.48(3), R₁ = 0.059, wR2 = 0.089, 1468 data, 193 parameters], Na₃Nd(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1059.78(18), b = 1207.25(15), c = 1645.7(4) pm, β = 99.742(17), R₁ = 0.047, wR₂ = 0.119, 1109 data, 351 parameters] and Na₃Pr(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1061.42(16), b = 1209.0(2), c = 1635.5(3) pm, β = 99.841(13), R₁ = 0.035, wR₂ = 0.062, 1323 data, 350 parameters] were obtained by careful crystallization at room temperature. A thorough structure discussion is given. The infrared spectrum of Nd(P₃O₉) · 4.5H₂O is also reported.     

Three Crystal Structures,One Chemical Formula – Barium Dihydrogen‐hypodiphosphate(IV)‐dihydrate,BaH2P2O6·2H2O

Three polymorphs of barium dihydrogen‐hypodiphosphate(IV)‐dihydrate, BaH₂P₂O₆ · 2H₂O ( A , B and C ), were obtained and structurally characterized by single‐crystal X‐ray diffraction. A crystallizes in the monoclinic space group P2₁/n (no. 14) with a = 7.459(1) Å, b = 8.066(1) Å, c = 12.460(2) Å, β = 91.27(1) ° and Z = 4. B crystallizes in the monoclinic space group C2/c (no. 15) with a = 11.049(8) Å, b = 6.486(3) Å, c = 10.956(6) Å, β = 106.89(5) ° and Z = 4. C crystallizes in the orthorhombic space group C222₁ (no. 20) with a = 9.193(3) Å, b = 6.199(2) Å, c = 12.888(4) Å and Z = 4. Discrete [H₂P₂O₆]^2– units, barium cations and water molecules, held together by intermolecular hydrogen bonds of the type O–H ··· O, build up the structures of the three polymorphs. The phase purity of A and C was verified by powder diffraction measurements.     

Transition Metal Complexes Containing Dihydrogen Hypodiphosphate in Eclipsed Conformation as Ligand: Preparation,Crystal Structure,Vibrational Spectra,and Thermal Behavior of K2[M(H2P2O6)2(H2O)2]·H2O (M = Co,Ni, Cu,and Zn)

The transition metal dihydrogen hypodiphosphate hydrates K₂[Co(H₂P₂O₆)₂(H₂O)₂] · H₂O ( 1 ), K₂[Ni(H₂P₂O₆)₂(H₂O)₂] · H₂O ( 2 ), K₂[Cu(H₂P₂O₆)₂(H₂O)₂] · H₂O ( 3 ) and K₂[Zn(H₂P₂O₆)₂(H₂O)₂] · H₂O ( 4 ) were synthesized and characterized by single crystal structure determination. The compounds 1 – 4 crystallize isotypic in the monoclinic space group C2/m (no. 12) with two formula units in the unit cell. The crystal structure is built up by [H₂P₂O₆]^2– units in an eclipsed conformation, by the corresponding transition metal, potassium cations, and water molecules. The eclipsed conformation of the [H₂P₂O₆]^2– has not been previously observed in none of known hypodiphosphates(IV) analyzed via X‐ray diffraction. However, its proposed based on spectroscopic methods. FT‐IR/FIR and FT‐Raman spectra of the crystalline salts were recorded and the thermal behavior of the compounds was investigated.     

Die Tetracyanoborsäuren H[B(CN)4]·n H2O,n = 0, 1, 2

The Tetracyanoboronic Acids H[B(CN)₄]·n H₂O, n = 0, 1, 2 Treatment of an aqueous solution of Na[B(CN)₄] with an acidic cation exchange resin leads to a solution of the strong tetracyanoboronic acid. Evaporation of the solution at room temperature yields colourless single crystals of [H₅O₂][B(CN)₄] ( , a = 9.5830(2) Å, c = 14.25440(3) Å, Z = 1). Further drying of [H₅O₂][B(CN)₄] (mp. 115 °C) in vacuum at 50 °C gives polycrystalline [H₃O][B(CN)₄] (P6₃mc, a = 8.704(1) Å, c = 6.152(1) Å, Z = 2), which is thermally stable up to 145 °C. The anhydrous polycrystalline acid H[B(CN)₄] is formed quantitatively by reacting Me₃SiNCB(CN)₃ with gaseous HCl. This acid starts to decompose at 190 °C with loss of HCN. All three acids were further characterized by vibrational spectroscopy, and elemental analysis.     

The Crystal Structures of Two No–Metal Tricyanomelaminates: Diammonium Tricyanomelaminate Dihydrate [NH4]2[C6N9H] · 2 H2O and Dimelaminium Tricyanomelaminate Melamine Dihydrate [C3N6H7]2[C6N9H] · C3N6H6 · 2 H2O

Diammonium tricyanomelaminate dihydrate [NH₄]₂[C₆N₉H] · 2 H₂O ( 1 ) and dimelaminium tricyanomelaminate melamine dihydrate [C₃N₆H₇]₂[C₆N₉H] · C₃N₆H₆ · 2 H₂O ( 2 ) were obtained by metathesis reactions from Na₃[C₆N₉] in aqueous solution and characterized by single‐crystal X‐ray diffraction and ¹⁵N solid‐state NMR spectroscopy ( 1 ). Both salts contain mono‐protonated tricyanomelaminate (TCM) anions and crystallize as dihydrates. Considering charge balance requirements, the crystal structure of 1 (C2/c, a = 3181.8(6) pm, b = 360.01(7) pm, c = 2190.4(4) pm, β = 112.39(3)°, V = 2319.9(8) 10⁶ · pm³) can best be described by assuming a random distribution of an ammonium ion – crystal water pair over two energetically similar sites. Apart from two melaminium cations, 2 (P2₁/c, a = 674.7(5) pm, b = 1123.6(5) pm, c = 3400.2(5) pm, β = 95.398(5), V = 2566(2) 10⁶ · pm³) contains one neutral melamine per formula unit acting as an additional “solvent” molecule and yielding a donor‐acceptor type of π–stacking interaction.     

Darstellung,Kristallstruktur, thermischer Abbau und Schwingungsspektren von [Co(NH3)6]2[Be4O(CO3)6] · 10 H2O

Preparation, Crystal Structure, Thermal Decomposition, and Vibrational Spectra of [Co(NH₃)₆]₂[Be₄O(CO₃)₆] · 10 H₂O [Co(NH₃)₆]₂[Be₄O(CO₃)₆] · 10 H₂O is a suitable compound for the quantitative determination of beryllium. It can be obtained by reaction of aqueous solutions of carbonatoberyllate with [Co(NH₃)₆]Cl₃. The crystal structure (trigonal‐rhombohedral, R3c (Nr. 161), a = 1071,6(1) pm, c = 5549,4(9) pm, V_EZ = 5519(1) · 10⁶ pm³, Z = 6, R1(I ≥ 2σ(I)) = 0,037, wR2(I ≥ 2σ(I)) = 0,094) contains [Co(NH₃)₆]³⁺‐ and [Be₄O(CO₃)₆]^6–‐ions, which are directly hydrogen bonded as well as with water molecules. The complex cations and anions occupy the positions of a distorted anti‐CaF₂‐type. The thermal decomposition, IR and Raman spectra are presented and discussed.     

Synthesis,Vibrational Spectrum and Structure of the Tetracyanoborate K[B(CN)4]·CH3CN

The new tetracyanoborate K[B(CN)₄]·CH₃CN was synthesized by dissolution of the solvent‐free K[B(CN)₄] in acetonitrile and subsequent careful crystallization. The crystal structure has been determined by single‐crystal X‐ray diffraction. It crystallizes in the orthorhombic space group P2₁2₁2₁ with Z = 4. Some comparisons with related structures are made, and the vibrational spectrum is discussed.     

Alkalimolybdotellurate: Darstellung und Kristallstruktur von Rb6[TeMo6O24] · 10H2O und Rb6[TeMo6O24] · Te(OH)6 · 6H2O

Alkaline Molybdotellurates: Preparation and Crystal Structures of Rb₆[TeMo₆O₂₄] · 10H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6H₂O Single crystals of Rb₆[TeMo₆O₂₄] · 10 H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O, respectively, were grown from aqueous solution. Rb₆[TeMo₆O₂₄] · 10 H₂O possesses the space group P1 . The lattice dimensions are a = 963.40(13), b = 972.56(12), c = 1 056.18(13) pm, α = 97.556(10), β = 113.445(9), γ = 102.075(10)°; Z = 1, 2 860 reflections, 215 parameters refined, R_g = 0.0257. The centrosymmetrical [TeMo₆O₂₄]^6? anions are stacked parallel to [010]. Rb(2) is coordinated with one exception by water molecules only. Folded chains consisting of [TeMo₆O₂₄]^6? anions and Rb(2) coordination polyhedra which are linked to pairs represent the prominent structural feature. Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O crystallizes monoclinically in the space group C2/c with a = 1 886.4(3), b = 1 000.9(1), c = 2 126.5(3) pm, and β = 115.90(1)°; Z = 4, 3 206 reflections, 240 parameters refined, R_g = 0.0333. It is isostructural in high extent with (NH₄)₆[TeMo₆O₂₄] · Te(OH)₆ · 7 H₂O. Hydrogen bonds between Te(OH)₆ molecules and [TeMo₆O₂₄]^6? anions establish infinite strands. The [TeMo₆O₂₄]^6? anions gather around Te(OH)₆ providing channel-like voids extending parallel to [001].     

[1,2‐P2S8]2− – a New Member of the Thiophosphate Family: Synthesis,Crystal Structure and Vibrational Spectrum of [NH4(2.2.2‐cryptand)]2[1,2‐P2S8] and [NH4(18‐crown‐6)]2[1,2‐P2S8]·H2O

Colourless block‐shaped crystals of [(NH₄)₂(2.2.2‐cryptand)₂][P₂S₈] ( 1 ) and [(NH₄)₂(18‐crown‐6)₂][P₂S₈]·H₂O ( 2 ) could be obtained by the reaction of an aqueous solution of ammonium hexathiohypodiphosphate, (NH₄)₄P₂S₆·2 H₂O, with sulfur and 2.2.2‐cryptand or 18‐crown‐6. The crystal structures of both compounds have been determined by single‐crystal X‐Ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group C2/c with a = 2032.7(2), b = 1243.6(2), c = 2244.6(2) pm, β = 98.64(1)°, and Z = 8, whereas compound 2 crystallizes also monoclinic in the space group P2₁/c with a = 2121.3(2), b = 865.5(1), c = 2345.4(2) pm, β = 91.96(1)°, and Z = 4. It could be established that the title compounds contain a new type of six‐membered [1,2‐P₂S₄] ring with P – P bond and three S – S linkages. The tetrahedral environment of each phosphorus is completed by a (formally) single and double bonded sulfur atom attached externally to the [1,2‐P₂S₄] ring. These terminal PS₂ units are mesomerically stabilized according to their P – S distances. FT‐IR and FT‐Raman spectra of the title compounds are recorded and interpreted.