The Unprecedented Tetrakis‐(disulfato)‐silicate Anion [Si(S2O7)4]4−, its Germanium Congener [Ge(S2O7)4]4−, and the Tris‐(disulfato)‐metallates [M(S2O7)3]2− (M=Si,Ge, Ti), Stabilized by Divalent Counter Cations B2+ (B=Sr,Ba, Pb)

The reaction of oleum (65 % SO₃) with the tetrachlorides of silicon, germanium, and titanium, respectively, led to the complex disulfates Sr₂[M(S₂O₇)₄] (M=Si, Ge), Ba[M(S₂O₇)₃] (M=Si, Ge, Ti) and Pb[M(S₂O₇)₃] (M=Ge, Ti) if strontium, barium, and lead were used as divalent counter cations. The strontium compounds exhibit the unique tetrakis‐(disulfato)‐metallate anions [M(S₂O₇)₄]^4? with the silicon and germanium atoms in octahedral coordination of two chelating and two monodentate disulfate groups. All of the other compounds display tris‐(disulfato)‐metallate anions [M(S₂O₇)₃]^2? with three chelating disulfate groups surrounding the M atoms. Thermoanalytical investigations on the germanium compounds Sr₂[Ge(S₂O₇)₄] and Ba[Ge(S₂O₇)₃] revealed their decomposition in multi‐step processes leading to a mixture of BSO₄ and BGe₄O₉ (B=Sr, Ba), while the thermal degradation of Pb[Ti(S₂O₇)₃] yields PbTiO₃. For selected examples, IR data are additionally presented.     

Dimers and Chains of Hydrogen bonded [HS2O7]– Anions in the Crystal Structures of M[HS2O7] (M = K, [NH4], [NO], Rb,Cs)

The reactions of KCl, [NH₄]₂[SO₄], Rb₂[CO₃], and Cs₂[CO₃] with fuming sulfuric acid (65 % SO₃) yielded colorless and moisture sensitive crystals of K[HS₂O₇] (monoclinic, P2₁/c (no. 14), Z = 4, a = 716.67(3) pm, b = 1043.57(4) pm, c = 828.78(3) pm, β = 107.884(1)°, V = 589.89(4) × 10⁶ pm³), [NH₄][HS₂O₇] (monoclinic, P2₁/c (no. 14), Z = 4, a = 729.29(1) pm, b = 1079.73(1) pm, c = 843.26(1) pm, β = 106.397(1)°, V = 637.01(1) × 10⁶ pm³), Rb[HS₂O₇] (monoclinic, P2₁/c (no. 14), Z = 4, a = 724.49(2) pm, b = 1073.19(3) pm, c = 852.01(3) pm, β = 106.534(1)°, V = 635.06(3) × 10⁶ pm³), and Cs[HS₂O₇] (triclinic, P$\bar{1}$ (no. 2), Z = 2, a = 537.61(3) pm, b = 784.71(4) pm, c = 867.93(4) pm, α = 94.214(2)°, β = 103.138(2)°, γ = 105.814(2)°, V = 339.47(3) × 10⁶ pm³). Colorless crystals of [NO][HS₂O₇] (monoclinic, P2₁/c (no. 14), Z = 4, a = 739.90(4) pm, b = 1048.00(5) pm, c = 830.97(4) pm, β = 106.985(2)°, V = 106.985(2) × 10⁶ pm³) were obtained as a side product from the reaction of [NH₄]₂[Rh(NO₂)₄] with oleum (65 % SO₃) in the ionic liquid [BMIm][OTf]. The crystal structures of K[HS₂O₇], [NH₄][HS₂O₇], [NO][HS₂O₇], and Rb[HS₂O₇] show the [HS₂O₇]^– ions linked into dimers by strong hydrogen bonds. Contrastingly, in the crystal structure of Cs[HS₂O₇] the [HS₂O₇]^– ions are connected to infinite chains. Raman spectra were recorded for M[HS₂O₇] (M = K, Rb, Cs).     

Coordination Chemistry of [Nb2(S2)2]4+ Clusters: Preparation and Crystal Structures of K4[Nb2(S2)2(C2O4)4] · 6 H2O and (NH4)6[Nb2(S2)2(C2O4)4](C2O4)

Bis(disulfido)bridged Nb^IV cluster oxalate complexes [Nb₂(S₂)₂(C₂O₄)₄]^4– were prepared by ligand substitution reaction from the aqua ion [Nb₂(μ‐S₂)₂(H₂O)₈]⁴⁺ and isolated as K₄[Nb₂(S₂)₂(C₂O₄)₄] · 6 H₂O ( 1 ), (NH₄)₆[Nb₂(S₂)₂(C₂O₄)₄](C₂O₄) ( 2 ) and Cs₄[Nb₂(S₂)₂(C₂O₄)₄] · 4 H₂O ( 3 ). The crystal structures of 1 and 2 were determined. The crystals of 1 belong to the space group P1, a = 720.94(7) pm, b = 983.64(10) pm, c = 1071.45(10) pm, α = 109.812(1)°, β = 91.586(2)°, γ = 105.257(2)°. The crystals of 2 are monoclinic, space group C2/c, a = 1567.9(2) pm, b = 1906.6(3) pm, c = 3000.9(4) pm, β = 95.502(2)°. The packing in 2 shows alternating layers of cluster anions and of ammonium/uncoordinated oxalates perpendicular to the [1 0 1] direction. Vibration spectra, electrochemistry and thermogravimetric properties of the complexes are also discussed.     

Sm4S3[Si2O7] und NaSm9S2[SiO4]6: Zwei Sulfidsilicate mit dreiwertigem Samarium

Sm₄S₃[Si₂O₇] and NaSm₉S₂[SiO₄]₆: Two Sulfide Silicates with Trivalent Samarium The sulfide silicates Sm₄S₃[Si₂O₇] and NaSm₉S₂[SiO₄]₆ are obtained as light yellow transparent crystals by the reaction of Sm, Sm₂O₃, S, and SiO₂ with fluxing SmCl₃ or NaCl, respectively, in suitable molar ratios in fused evacuated silica tubes (850 °C, 7 d). Tetragonal crystals of Sm₄S₃[Si₂O₇] (I4₁/amd; Z = 8; a = 1186.4(1); c = 1387.0(2) pm) with ecliptically conformed [Si₂O₇]^6–‐groups of corner sharing [SiO₄]‐tetrahedra are formed. These double tetrahedra as well the sulfide anions (S^2–) coordinate two crystallographically independent metal cations. They provide coordination numbers of 8 + 1 (5 S^2– and 3 + 1 O^2–) for Sm1 and 9 (3 S^2– and 6 O^2–) for Sm2. NaSm₉S₂[SiO₄]₆ crystallizes hexagonally (P6₃/m; Z = 1; a = 975.32(9); c = 676.46(7) pm) in a modified bromapatite‐type structure. The coordination spheres about the two crystallographically different Sm³⁺ cations are built up by oxygen atoms of the orthosilicate units ([SiO₄]^4–) and sulfide anions (S^2–). As a result, Sm1 and Sm2 have coordination numbers of 9 and 8, respectively. Na⁺ and (Sm1)³⁺ occupy the position 4 f in a molar ratio of 1 : 3 whereas the lower coordinated (Sm2)³⁺ occupies the 6 h position.     

Pr4S3[Si2O7] und Pr3Cl3[Si2O7]: Durch weiche Fremdanionen modifizierte Derivate von Praseodymdisilicat

Pr₄S₃[Si₂O₇] and Pr₃Cl₃[Si₂O₇]: Derivatives of Praseodymium Disilicate Modified by Soft Foreign Anions For synthesizing both the disilicate derivatives Pr₄S₃[Si₂O₇] and Pr₃Cl₃[Si₂O₇], Pr, Pr₆O₁₁ and SiO₂ are brought to reaction with S and PrCl₃, respectively, in suitable molar ratios (850 °C, 7 d) in evacuated silica tubes. By using NaCl as a flux, Pr₄S₃[Si₂O₇] crystallizes as pale green, transparent single crystals (tetragonal, I4₁/amd, a = 1201.6(1), c = 1412.0(2) pm, Z = 8) with the appearance of slightly compressed octahedra. On the other hand, Pr₃Cl₃[Si₂O₇] emerges as pale green, transparent platelets and crystallizes monoclinically (space group: P2₁, a = 530.96(6), b = 1200.2(1), c = 783.11(8) pm, β = 109.07(1)°, Z = 2). In both crystal structures ecliptically conformed [Si₂O₇]^6– units of two corner‐linked [SiO₄] tetrahedra with Si–O–Si bridging angles of 131° in the sulfide and 148° in the chloride disilicate are present. In Pr₄S₃[Si₂O₇] both crystallographically independent Pr³⁺ cations show coordination numbers of 8 + 1 (5 S^2– and 3 + 1 O^2–) and 9 (3 S^2– and 6 O^2–). For Pr1, Pr2 and Pr3 in Pr₃Cl₃[Si₂O₇] coordination numbers of 10 (5 Cl^– and 5 O^2–) and 9 (2 ×; 4 Cl^– and 5 O^2– or 3 Cl^– and 6 O^2–, respectively) occur.     

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S2O7)3]2− Ions (M=Si,Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag)

The reactions of group 14 tetrachlorides MCl₄ (M=Si, Ge, Sn) with oleum (65 % SO₃) at elevated temperatures lead to the unique complex ions [M(S₂O₇)₃]^2?, which show the central M atoms in coordination with three chelating S₂O₇^2? groups. The mean distances M? O within the anions increase from 175.6(2)–177.5(2) pm (M=Si) to 186.4(4)–187.7(4) pm (M=Ge) to 201.9(2)–203.5(2) pm (M=Sn). These distances are reproduced well by DFT calculations. The same calculations show an increasing positive charge for the central M atom in the row Si, Ge, Sn, which can be interpreted as the decreasing covalency of the M? O bonds. For the silicon compound (NH₄)₂[Si(S₂O₇)₃], ²⁹Si solid‐state NMR measurements have been performed, with the results showing a signal at ?215.5 ppm for (NH₄)₂[Si(S₂O₇)₃], which is in very good agreement with theoretical estimations. In addition, the vibrational modes within the [MO₆] skeleton have been monitored by Raman spectroscopy for selected examples, and are well reproduced by theory. The charge balance for the [M(S₂O₇)₃]^2? ions is achieved by monovalent A⁺ counter ions (A=NH₄, Ag), which are implemented in the syntheses in the form of their sulfates. The sizes of the A⁺ ions, that is, their coordination requirements, cause the crystallographic differences in the crystal structures, although the complex [M(S₂O₇)₃]^2? ions remain essentially unaffected with the different A⁺ ions. Furthermore, the nature of the A⁺ ions influences the thermal behavior of the compounds, which has been monitored for selected examples by thermogravimetric differential thermal analysis (DTA/TG) and XRD measurements.     

Die Reaktionen von Trithiazylchlorid mit Zirkoniumtetrachlorid Die Kristallstruktur von (S4N4CI)2[Zr2CI10]

Reactions of Zirconium Tetrachloride with Trithiazylchloride. Crystal Structure of (S₄N₄)[Zr₂Cl₁₀] Zirconium tetrachloride reacts with (NSCI)₃ yielding (S₃N₃CI₂)₂[Zr₂CI₁₀], S₄N₄[Zr₂CI₁₀], or (S₄N₄CI)₂[Zr₂CI₁₀], depending of the reaction conditions. These compounds were characterized by their i.r. spectra. They have an ionic structure containing the known ions S₃N₃CI₂⊕, S₄N₄^2⊕, S₄N₄CI^⊕, and the thus far unknown [Zr₂CI₁₀]^2? ion. According to the X-ray structure determination (2827 independent observed reflexions, R = 0.027), (S₄N₄CI)₂[Zr₂CI₁₀] crystallizes in the space group P&1macr; with the lattice constants a = 688, b = 1132, c = 1827 pm, α = 103.2°, β = 98.7° and γ = 91.9⁰ and with Z = 2 formula units per unit cell. The structure is built up from S₄N₄CI^⊕ ions, which are nearly identical as in S₄N₄CI[FeCI₄] and from [Zr₂CI₁₀]^2? ions in which two chloro bridges join two edge-sharing octahedra.     

Synthese und Kristallstrukturen von (PPh4)2[TeS3] · 2 CH3CN und (PPh4)2[Te(S5)2]

Synthesis and Crystal Structures of (PPh₄)₂[TeS₃] · 2 CH₃CN and (PPh₄)₂[Te(S₅)₂] (PPh₄)₂[TeS₃] · 2 CH₃CN was obtained by the reaction of PPh₄Cl, Na₂S₄ and Te in acetonitrile. With sulfur it reacts yielding (PPh₄)₂[Te(S₅)₂]. The crystal structures of both products were determined by X-ray diffraction. (PPh₄)₂[TeS₃] · 2 CH₃CN: triclinic, space group P1 , Z = 2, R = 0.041 for 4 629 reflexions; it contains trigonal-pyramidal [TeS₃]^2? ions with an average Te? S bond length of 233 pm. (PPh₃)₂[Te(S₅)₂]: monoclinic, P2₁/n, Z = 2, R = 0.037 for 2 341 reflexions. In the [Te(S₅)₂]^2? ion the tellurium atom has a nearly square coordination by four S atoms. Along with the Te atoms each of the two S₅ groups forms a ring with chair conformation.     

(Se4)2[Mo2O2Cl8][MCl6](M = Zr,Hf) — Tetraselenium(2+)Halometalates with two Different Anions

The reaction of Se₄[Mo₂O₂Cl₈] with Se₄[MCl₆] (M = Zr, Hf) or of Se, SeCl₄, MoOCl₄, and MCl₄ (M = Zr, Hf) at 120 °C in sealed evacuated glass ampoules gives (Se₄)₂[Mo₂O₂Cl₈][MCl₆] (M = Zr, Hf) in the form of dark‐green, air sensitive crystals in quantitative yield. The crystal structure analyses of both isotypic compounds (monoclinic, P2₁/c, Z = 2, a = 1336(2), b = 716(1), c = 1518(4) pm, β = 106.0(2)° for M = Zr; a = 1334.1(8), b = 715.03(9), c = 1518.2(3) pm, β = 106.00(2)° for M = Hf) show the presence of square‐planar Se₄²⁺, of dinuclear [Mo₂O₂Cl₈]^2—, and of almost regular octahedral [MCl₆]^2— ions. X‐ray crystallographic investigations on (Se₄)₂[Mo₂O₂Cl₈][ZrCl₆] give no hint for solid state phase transitions between —160 and 200 °C. This is in contrast to the related compounds Se₄[Mo₂O₂Cl₈] and Se₄[ZrCl₆] which both undergo phase transitions accompanied by reorientation of the cations and anions. (Se₄)₂[Mo₂O₂Cl₈][ZrCl₆] is paramagnetic and obeys the Curie‐Weiss law with a Weiss constant of —4(7) K indicating only weak interaction between the paramagnetic centres. The magnetic moment of 1.7(1) μ_B is consistent with the presence of Mo^V (d¹ configuration) and supports the ionic formula.     

Das SCN–-Ion als ambidenter Ligand – Synthese und Kristallstrukturen von (Bu4N)4[Ag2Fe2(SCN)12] und (Et4N)2 [Ag2Fe(SCN)6]

The SCN^– Ion as an Ambidentate Ligand – Synthesis and Crystal Structures of (Bu₄N)₄[Ag₂Fe₂(SCN)₁₂] and (Et₄N)₂ [Ag₂Fe(SCN)₆] In (Bu₄N)₄[Ag₂Fe₂(SCN)₁₂] · 2 CH₃NO₂ ( 1 ) and (Et₄N)₂[Ag₂Fe(SCN)₆] ( 2 ) the ambidentate SCN^– anions link Ag⁺ with Fe³⁺ and Fe²⁺ centers, respectively. The tetranuclear anions in 1 are built from [Fe(NCS)₆]^3– groups connected by Ag⁺ ions. In 2 the same bridging pattern leads to polymeric anionic chains containing [Fe(NCS)₆]^4– groups linked by Ag⁺ ions. (Bu₄N)₄[Ag₂Fe₂(SCN)₁₂] · 2 CH₃NO₂ ( 1 ): a = 1184.10(10), b = 1370.80(10), c = 1776.5(2) pm, α = 99.090(10), β = 102.100(10), γ = 100.360(10)°, V = 2715.5(4) · 10⁶ pm³, space group P1; (Et₄N)₂[Ag₂Fe(SCN)₆] ( 2 ): a = 1607.0(2), b = 1006.92(9), c = 1096.13(9) pm, V = 1773.7(3) · 10⁶ pm³, space group Pnnm.     

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).     

Palladium(IV) in an Oxoanionic Environment: The XeF2 Assisted Synthesis of [Pd(S2O7)3]2−

For the first time tetravalent palladium is detected, coordinated exclusively by simple oxoanions. Stabilization was achieved by formation of the [Pd(S₂O₇)₃]^2? complex in which three chelating disulfate groups surround the metal atom. The salt K₂[Pd(S₂O₇)₃] could only be obtained if the reaction of K₂[PdCl₆] and neat SO₃ was performed in the presence of XeF₂.     

Structural Patterns and Dimensionality in Magnesium Borophosphates: The Crystal Structures of Mg2(H2O)[BP3O9(OH)4] and Mg(H2O)2[B2P2O8(OH)2]·H2O

Hydrothermal investigations in the system MgO/B₂O₃/P₂O₅(/H₂O) yielded two new magnesium borophosphates, Mg₂(H₂O)[BP₃O₉(OH)₄] and Mg(H₂O)₂[B₂P₂O₈(OH)₂]·H₂O. The crystal structures were solved by means of single crystal X‐ray diffraction. While the acentric crystal structure of Mg₂(H₂O)[BP₃O₉(OH)₄] (orthorhombic, P2₁2₁2₁ (No. 19), a = 709.44(5) pm, b = 859.70(4) pm, c = 1635.1(1) pm, V = 997.3(3) × 10⁶ pm³, Z = 4) contains 1D infinite chains of magnesium coordination octahedra interconnected by a borophosphate tetramer, Mg(H₂O)₂[B₂P₂O₈(OH)₂]·H₂O (monoclinic, P2₁/c (No. 14), a = 776.04(5) pm, b = 1464.26(9) pm, c = 824.10(4) pm, β = 90.25(1)°, V = 936.44(9) × 10⁶ pm³,Z = 4) represents the first layered borophosphate with 6³ net topology. The structures are discussed and classified in terms of structural systematics.     

Über Thallium(I)-chlorooxomolybdate: Synthese und Kristallstrukturen von Tl[MoOCl4(NCCH3)], Tl[Mo2O2Cl7] und Tl2[Mo4O4Cl14] und die Struktur von Tl2[MoCl6]

On Thallium(I)-oxochloromolybdates: Synthesis and Crystal Structures of Tl[MoOCl₄(NCCH₃)], Tl[Mo₂O₂Cl₇], and Tl₂[Mo₄O₄Cl₁₄] and the Structure of Tl₂[MoCl₆] Black crystals of Tl₂[MoCl₆] are formed in the reaction of TlCl with MoOCl₃ in a sealed evacuated glass ampoule at 350 °C. The crystal structure analysis shows that Tl₂[MoCl₆] (cubic, Fm 3¯m, a = 986.35(7) pm) adopts the K₂[PtCl₆] structure with a Mo–Cl bond length of 236.6 pm. Tl[MoOCl₄(NCCH₃)] was obtained by the reaction of TlCl with MoOCl₃ in acetonitrile in form of yellow, moisture sensitive crystals. The structure (orthorhombic, Cmcm, a = 746.0(1), b = 1463.8(3), c = 857.3(2) pm) is built of Tl⁺ cations and octahedral [MoOCl₄(NCCH₃)]^– anions in which the acetonitrile ligand is bound in trans position to the oxygen. The reaction of TlCl and MoOCl₃ in dichloromethane yields Tl[Mo₂O₂Cl₇] and Tl₂[Mo₄O₄Cl₁₄] as green moisture sensitive crystals. The structure of Tl[Mo₂O₂Cl₇] (orthorhombic, Pmmn, a = 694.3(1), b = 951.9(2), c = 904.7(1) pm) consists of Tl⁺ cations and dinuclear [Mo₂O₂Cl₇]^– anions, with two equidistant chlorine bridges of 248.2 and one longer chlorine bridge of 265.7 pm. The oxygen atoms are located in the trans positions of the longer chloro bridge. The structure of Tl₂[Mo₄O₄Cl₁₄] (triclinic, P1¯, a = 692.8(1), b = 919.6(1), c = 998.9(1) pm, α = 104.94(1)°, β = 90.31(1)°, γ = 108.14(1)°) is build of Tl⁺ cations and [Mo₄O₄Cl₁₄]^2– anions which form tetramers of distorted octahedral, edgesharing (MoOCl₅) units with chlorine atoms in the bridging positions. The oxygen atoms are located in the trans positions of the longest chlorine bridges.     

K2NdP2S7: A Mixed‐Valent Neodymium(III) Thiophosphate According to K4Nd2[PS4]2[P2S6] with Discrete [PS4]3– and [S3P–PS3]4– Anions

Pale blue, lath‐shaped single crystals of K₂NdP₂S₇ (≡ K₄Nd₂[PS₄]₂[P₂S₆]; monoclinic, P2₁/n, a = 904.76(8), b = 677.38(6), c = 1988.7(2) pm, β = 97.295(5)°, Z = 2) are obtained by the reaction of Nd, S and P₂S₅ with an excess of KCl as a flux in evacuated silica tubes at 750 °C (7 d) which should produce Nd[PS₄] instead. Beside isolated [PS₄]^3– tetrahedra, the crystal structure contains discrete ethane‐analogous [P₂S₆]^4– (≡ [S₃P–PS₃]^4–) units in staggered conformation with tetravalent phosphorus cations and a P–P distance of 219 pm. The two crystallographically different potassium cations show coordination numbers of nine and ten in the shape of distorted mono‐ and bicapped square antiprisms. Finally, the Nd³⁺ cations are surrounded by eight sulfur atoms arranged as (uncapped) square antiprisms. The entire structure is dominated by (K1)⁺ containing {(Nd₂[PS₄]₂[P₂S₆])^4–} layers parallel (101) which are three‐dimensionally interconnected by (K2)⁺ cations.     

Synthese und Kristallstrukturen von (NEt4)2[TeS3], (NEt4)2[Te(S5)(S7)] und (NEt4)4[Te(S5)2][Te(S7)2]

Synthesis and Crystal Structures of (NEt₄)₂[TeS₃], (NEt₄)₂[Te(S₅)(S₇)], and (NEt₄)₄[Te(S₅)₂][Te(S₇)₂] (NEt₄)₂[TeS₃] was obtained by the reaction of NEt₄Cl, Na₂S₄ and tellurium in acetonitrile. It reacts with sulfur, yielding (NEt₄)₂[Te(S₅)(S₇)], which is transformed to (NEt₄)₄[Te(S₅)₂][Te(S₇)₂] by recrystallization from hot acetonitrile. According to the X-ray structure analysis, crystals of (NEt₄)₂[TeS₃] are monoclinic (space group P2₁/c) and form twins with the twinning plane (001); they contain pyramidal TeS₃^2– ions. (NEt₄)₂[Te(S₅)(S₇)] forms triclinic twins (space group P1) with the twinning plane (010). In the [Te(S₅)(S₇)]^2– ion an S₅ and an S₇ atom group are bonded in a chelate manner to the tellurium atom, which has square coordination. (NEt₄)₄[Te(S₅)₂][Te(S₇)₂] (monoclinic, space group P2₁/c) contains two kinds of anions, the known [Te(S₅)₂]^2– and the new [Te(S₇)₂]^2– ion which has two S₇ chelating groups.     

Na1.89Ag0.11[BP2O7(OH)] und Na2[BP2O7(OH)] – Isotype Borophosphate mit Tetraeder-Schichtpaketen

Na_1.89Ag_0.11[BP₂O₇(OH)] and Na₂[BP₂O₇(OH)] – Isotypic Borophosphates Containing Layered Tetrahedral Blocks The isotypic borophosphates Na_1.89Ag_0.11[BP₂O₇(OH)] and Na₂[BP₂O₇(OH)] were grown under mild hydrothermal conditions (T = 165–170 °C). The crystal structures were solved by single crystal methods in the case of Na_1.89Ag_0.11[BP₂O₇(OH)] and by refinement of powder data (Rietveld method) for Na₂[BP₂O₇(OH)], respectively (orthorhombic, Pna2₁ (No. 33); a = 683.98(14)/682.36(1) pm, b = 2086.5(4)/2079.11(4) pm, c = 1318.9(3)/1314.46(3) pm; Z = 12). The compounds contain a complex two-dimensional structure consisting of layered tetrahedral blocks, which are formed by six- and eight-membered rings of tetrahedra. The Na⁺/Ag⁺-ions are located inside and near the surface of the ‘layer blocks' and are five-, six- and sevenfold coordinated by oxygen.     

Synthesis and Characterization of the Chain Borosulfates (NH4)3[B(SO4)3] and Sr[B2(SO4)4]

Two new borosulfates were obtained either by an open vessel synthesis from sulfuric acid and B(OH)₃, yielding (NH₄)₃[B(SO₄)₃] or from solvothermal synthesis in oleum enriched sulfuric acid and B(OH)₃, yielding Sr[B₂(SO₄)₄]. (NH₄)₃[B(SO₄)₃] crystallizes homeotypic to K₃[B(SO₄)₃] in space group Ibca (Z = 8, a = 728.58(3) pm, b = 1470.84(7) pm, c = 2270.52(11) pm), comprising open branched vierer single chains {¹_∞[B(SO₄)₂(SO₄)_2/2]^3–}. Sr[B₂(SO₄)₄] crystallizes as an ordered variant of Pb[B₂(SO₄)₄] in space group Pnna (Z = 4, a = 1257.4(4) pm, b = 1242.1(4) pm, c = 731.9(2) pm), consisting of loop branched vierer single chains {¹_∞[B(SO₄)_4/2]^2–}. Vibrational spectroscopy confirms both refined structure models. Thermal analysis of the dried powders, showed a decomposition towards the binary and ternary components, whereas a thermal treatment in the presence of the mother liquor promotes a decomposition of Sr[B₂(SO₄)₄] towards Sr[B₂O(SO₄)₃].     

Reaction with SO3 in Ionic Liquids: The Example of K2(S2O7)­(H2SO4)

The ionic liquid 1‐butyl‐3‐methylimidazolium hydrogensulfate, [bmim]HSO₄, turned out to be resistant even to strong oxidizers like SO₃. Thus, it should be a suitable solvent for the preparation of polysulfates at low temperatures. As a proof of principle we here present the synthesis and crystal structure of K₂(S₂O₇)(H₂SO₄), which has been obtained from the reaction of K₂SO₄ and SO₃ in [bmim]HSO₄. In the crystal structure of K₂(S₂O₇)(H₂SO₄) (orthorhombic, Pbca, Z = 8, a = 810.64(2) pm, b = 1047.90(2) pm, c = 2328.86(6) pm, V = 1978.30(8) ų) two crystallographically unique potassium cations are coordinated by a different number of monodentate and bidentate‐chelating disulfate anions as well as by sulfuric acid molecules. The crystal structure consists of alternating layers of [K₂(S₂O₇)] slabs and H₂SO₄ molecules. Hydrogen bonds between hydrogen atoms of sulfuric acid molecules and oxygen atoms of the neighboring disulfate anions are observed.