Neue Tetrapnictidotitanate(IV): Na3M3[TiX4] mit M  Na/Sr,Na/Eu und X  P,As

New Tetrapnictidotitanates(IV): Na₃M₃[TiX₄] with M ? Na/Sr, Na/Eu and X ? P, As The four novel tetrapnictidotitanates(IV) Na₄Sr₂TiP₄, Na₄Sr₂TiAs₄, Na_4.3Eu_1.7TiP₄ and Na_4.3Eu_1.7TiAs₄ were prepared from the binary pnictides NaX, M₃X, M′X (X ? P, As and M′ ? Sr, Eu) and elementary titanium in tantalum ampoules. The air and moisture sensitive transition metal compounds form dark red hexagonal crystals. They are semiconductors with E_g = 1.8eV (Sr) and E_g = 1.3eV (Eu), respectively. The compounds are isotypic with Na₆ZnO₄ (space group P6₃mc (no. 186); hP22; Z = 2; Na₄Sr₂TiP₄; a = 936.8(1) pm, c = 740.5(1) pm; Na₄Sr₂TiAs₄: a = 958.2(1) pm, c = 757.1(1) pm; Na_4.3Eu_1.7TiP₄: a = 929.9(2) pm, c = 732.0(2) pm; Na_4.3Eu_1.7TiAs₄: a = 953.9(1) pm, c = 749.5(1) pm). Main structural units are polar oriented [TiP₄]^8? and [TiAs₄]^8? tetrahedral anions with d (Ti? P) = 240.2(3) pm and d (Ti? As) = 248.6(3) pm.     

Pniktogenidostannate(IV) mit isolierten Tetraeder‐Anionen: Neue Vertreter (E1)4(E2)2[Sn(E15)4] (mit E1 = Na,K; E2 = Ca,Sr, Ba; E15 = P,As, Sb,Bi) vom Na6[ZnO4]‐Typ und die Überstrukturvariante von K4Sr2[SnAs4]

Pnictogenidostannates(IV) with Discrete Tetrahedral Anions: New Representatives (E1)₄(E2)₂[Sn(E15)₄] (with E1 = Na, K; E2 = Ca, Sr, Ba; E15 = P, As, Sb, Bi) of the Na₆[ZnO₄] Type and the Superstructure Variant of K₄Sr₂[SnAs₄] The silvery to dark metallic lustrous compounds (E1)₄(E2)₂[Sn(E15)₄] (E1 = Na, K; E2 = Ca, Sr, Ba; E15 = P, As, Sb, Bi) were prepared from melts of stoichiometric mixtures of the elements. They crystallize in the Na₆[ZnO₄]‐type structure (hexagonal, space group: P6₃mc, Z = 2; Na₄Ca₂[SnP₄]: a = 938.94(7), c = 710.09(8) pm; K₄Sr₂[SnAs₄]: a = 1045.0(2), c = 767.0(1) pm; K₄Ba₂[SnP₄]: a = 1029.1(6), c = 780.2(4) pm; K₄Ba₂[SnAs₄]: a = 1051.3(1), c = 795.79(7) pm; K₄Ba₂[SnSb₄]: a = 1116.9(2), c = 829.2(1) pm; K₄Ba₂[SnBi₄]: a = 1139.5(2), c = 832.0(2) pm). The anionic partial structure consists of tetrahedra [Sn(E15)₄]^8– orientated all in the same direction along [001]. In the cationic partial structure one of the two cation positions is occupied statistically by alkali and alkaline earth metal atoms. Up to now only for K₄Sr₂[SnAs₄] a second modification could be isolated, forming a superstructure type with three times the unit cell volume (hexagonal, space group: P6₃cm, Z = 6; a = 1801.3(2), c = 767.00(9) pm) and an ordered cationic partial structure.     

First Observation of an Inverse Ruddlesden‐Popper Series: (A3n+1ONn−1)Bin+1 with A = Sr,Ba and n = 1, 3

Single crystals ((Ba_0.78(1)Sr_0.22)₄O)Bi₂ and ((Ba_0.62(1)Sr_0.38)₁₀N₂O)Bi₄ were successfully prepared from melt beads of Ba, Sr, and Bi in nitrogen atmosphere with oxygen impurities. The phases can be prepared in single phase from the appropriate mixtures of alkaline‐earth metal, bismuth, and bismuth oxide upon heating in pure nitrogen atmosphere. ((Ba_0.78(1)Sr_0.22)₄O)Bi₂ crystallizes in the K₂NiF₄ structure type (space group I4/mmm, No. 139, a = 522.34(5) pm, c = 1844.0(2) pm, Z = 2, R_gt(F) = 0.039) with layers of vertex‐sharing octahedra ((Ba,Sr)_4/2Ba₂O). ((Ba_0.62(1)Sr_0.38)₁₀N₂O)Bi₄ crystallizes as an isotype of Sr₄Ti₃O₁₀ (space group I4/mmm, No. 139, a = 531.3(1) pm, c = 3983.2(4) pm, Z = 2, R_gt(F) = 0.050) containing slabs of three layers of vertex‐sharing octahedra further connected via corners. These compounds are interpreted in terms of members of an inverse Ruddlesden‐Popper series with the general formula n (A₃ON_n?1)Bi · ABi or (A_3n+1ON_n?1)Bi_n+1, respectively, with n = 1, 3. Partial order of the alkaline‐earth metal ions is analyzed.     

Ba2(CN2)(CN)2 und Sr2(CN2)(CN)2 – die ersten gemischten Cyanamid-cyanide

Ba₂(CN₂)(CN)₂ and Sr₂(CN₂)(CN)₂ – the First mixed Cyanamide Cyanides The mixed cyanamide-cyanides M₂(CN₂)(CN)₂ (M = Ba, Sr) were synthesized by the reaction of Ba₂N and SrCO₃, respectively, with HCN at 630°C. The crystal structure of Ba₂(CN₂)(CN)₂ was determined from single-crystal X-ray investigations at room temperature and ?100°C; the isostructural Sr₂(CN₂)(CN)₂ was refined using powder methods (P6₃/mmc; Ba₂(CN₂)(CN)₂: a = 1 066.52(5) pm, c=696.82(3) pm; Sr₂(CN₂)(CN)₂: a = 1 035.91(1) pm, c = 664.23(1) pm; Z = 4). The crystal structure is a partially filled defect variant of the anti-NiAs structure type with a distorted hexagonal close packed arrangement of M²⁺-ions. All CN₂^2? and one quarter of the CN^? ions occupy 3/4 of the octahedrally coordinated interstices, the remaining cyanide anions are located at 3/8 of the tetrahedral sites. In the crystal structure the CN^? are coordinated to the cations both end-on and side-on. All anions can be distinguished by vibrational spectroscopy.     

Verbindungen A3M5 (A = Erdalkalimetall,M = Triel/Tetrel): Eine Fallstudie zur strukturellen und elektronischen Stabilität polarer intermetallischer Phasen

Compounds A₃M₅ (A = alkaline earth, M = triel/tetrel): A Case Study on Structural and Electronic Factors Stabilizing Polar Intermetallics Starting from the non electron precise binary compounds Ca₃Ga₅/Sr₃In₅ (Hf₃Ni₂Si₃ type) and Ba₃Al₅ at one hand and Ba₃Pb₅ (Pu₃Pd₅ type) at the other hand, a series of new ternary intermetallics of the general formula A₃M₅ (A: alkaline earth, M: triel/tetrel) has been synthesized, structurally characterized and studied by band structure calculations. The chemical substitution of M in A₃M₅ allows, via the continous variation of the radius ratio (r_A:r_M) and the valence electron number (VE/M) the detection of the geometrically and electronically determined stability ranges of the three structure types formed by the binary compounds. At values of r_A:r_M between 1.30 and 1.52 in the triel rich region of A₃M′_xM″_5?x the Hf₃Ni₂Si₃ type (orthorhombic, space group Cmcm) is formed: In Ca₃Ga₅ up to 1.8 Ga can be substituted by Al, in Sr₃In₅ similar amount of In can be replaced by either Al or Ga. The mixed trielide Sr₃Al_2.6Ga_2.4 (a = 468.4(1), b = 1132.5(1), c = 1570.0(2) pm, R1 = 0.0261) can be obtained, although both corresponding binary phases are not known. At larger values of the ratio r_A/r_M as in Ba₃Al₃Ga₂ (Ba₃Al₅ type, hexagonal, space group P6₃/mmc, a = 598.9(1), c = 1456.0(3) pm, R1 = 0.0353) layers of condensed M₅ building blocks with Al‐Al partial bonds are formed. Substituting one In position in Sr₃In₅ against Pb results in the isotypic, but electron precise Zintl compound Sr₃In₄Pb (a = 506.1(1), b = 1191.8(3), c = 1650.2(4) pm, R1 = 0.0286), where the Fermi level in shifted into a distinct minimum of the density of states. Conversely, at the tetrele rich end of the series A₃In_xPb_5?x, characterized by compounds of the Pu₃Pd₅ type (orthorhombic, space group Cmcm) with almost isolated nido clusters M₅, a minimum of the DOS can be reached, if Pb is partially substituted by In (A₃In_xPb_5?x with A = Sr/Ba: x = 0.7/0.6; a = 1084.6(2)/1118.6(2), b = 867.1(2)/904.4(1), c = 1104.8(2)/1133.9(2) pm, R1 = 0.0394/0.0434).     

Sr13□NbAs11 and Eu13□NbAs11 – Defect Variants of the Ca14AlSb11 Structure with asymmetric [As3]7− anions

The novel compounds Sr₁₃NbAs₁₁ and Eu₁₃NbAs₁₁ have been synthesized from SrAs, Eu₅As₄, Sr, Nb and As in niobium ampoules at 1173–1273 K. The tetragonal tI 200 phases are defect variants of the Ca₁₄AlSb₁₁ structure (space group I4₁/acd (no. 142); Sr₁₃□NbAs₁₁: a = 1649.8(2) and c = 2214.1(3); Eu₁₃□NbAs₁₁: a = 1632.9(8) and c = 2197.3(8) pm; Z = 8). The structures are built from the cations Sr²⁺, and Eu²⁺, respectively, and from the anions [NbAs₄]^7?, As^3?, and the linear polyanion [As₃]^7?. This polyanion (isosteric to I₃^?) is asymmetric with d(As? As) = 273.0 and 346.0 pm (Sr) and 274.7 and 335.6 pm (Eu), respectively. The bond lengths in the tetrahedral anions are d(Nb? As) = 250.8 and 251.1 pm. The complete structural arrangement is related to that of Cu₂O by forming two interpenetrating networks. The oxygen atoms are substituted by niobium centered As₄ tetrahedra, and the Cu atoms are substituted by As₆ octahedra (centered by Sr, Eu). The central As atoms of the polyanions connect the nets. Both As networks are enveloped by the remaining cations forming cubes, tetragonal antiprisms and capped trigonal prisms.     

Neue ternäre Käfigverbindungen aus den Systemen Barium–Indium/Zink/Cadmium–Germanium: Zintl-Verbindungen mit Phasenbreite?

New Ternary Clathrate Compounds in the Systems Barium–Indium/Zinc/Cadmium–Germanium: Zintl Compounds with Phase Width? By systematic investigations in the systems barium–indium/zinc/cadmium–germanium we found a couple of new electrovalent ternary compounds with A₈X₄₆ clathrate (I) type structures. They crystallize cubically in space-group Pm3n. For Ba₈In₁₆Ge₃₀ (a = 1 075.8 pm), Ba₈Zn₈Ge₃₈ (a = 1 082.0 pm) and Ba₈Cd₈Ge₃₈ (a = 1 096.0 pm) the structures were verified by X-ray single crystal diffraction data. According to valence and bounding distances the new clathrates should be Zintl compounds. Measurements of the temperature dependence of the electrical resistivity proved, that they are indeed semiconductors. A part of the 2B/3B metal atoms can be substituted by germanium. Charge balance will be retained by creation of vacancies in the A₈X₄₆ type structures. By phase analysis the limits of the composition range were determined as Ba₈In₄Ge₉[]₃Ge₃₀ (a = 1 084.9 pm), Ba₈Zn₄Ge₁₀[]₂Ge₃₀ (a = 1 073.6 pm) and Ba₈Cd₄Ge₁₀[]₂Ge₃₀ (a = 1 082.0 pm).     

Synthese,Struktur und Eigenschaften der Tetraarsenidometallate(V) M7[TAs4] (M = K,Rb; T = Nb,Ta)

Synthesis, Structure, and Properties of the Tetraarsenidometallates(V) M₇[TAs₄] (M = K, Rb; T = Nb, Ta) The tetraarsenidometallates(V) M₇[TAs₄] (M = K, Rb; T = Nb, Ta) have been prepared from RbAs, KAs, Rb₃As, K₃As, and Nb or Ta in sealed Nb(Ta) ampoules at T = 1100 K. They crystallize in a new structure type oP24 (Pmn2₁, no. 31); K₇[NbAs₄]: a = 1019.2(2) pm, b = 916.2(2) pm, c = 830.6(1) pm; K₇[TaAs₄]: a = 1017.3(2) pm, b = 915.5(2) pm, c = 830.5(2) pm; Rb₇[NbAs₄]: a = 1059.2(4) pm, b = 952.8(4) pm, c = 860.4(4) pm; Z = 2 formula units per unit cell). The compounds form dark red crystals and they are sensitive against air and moisture. They are semiconductors with E_g = 1.80 eV. The thermal decomposition in dynamical vacuum gives evidence for the existance of K₄TAs₃ and K₂TAs₂ (T = Nb, Ta). Main structural units are polar oriented tetrahedra [TAs₄] with d (T – As) = 252.2(1) pm; 251.3(1) pm; 253.0(4) pm, respectively. The As atoms are trigonal prismatically coordinated by M and T atoms. These trigonal prisms form anionic and cationic layers [M₄As₂]^2? and _∞²[M₃TAs₂]²⁺ alternating along the b axis. The structure is comparable with that of Co₂P and can be described as a stuffed shear variant of the Na₆□ZnO₄ type of structure.     

Crystal and Electronic Structure and Optical Properties of AE2SiP4 (AE = Sr,Eu, Ba) and Ba4Si3P8

Three new compounds in the AE‐Si‐P (AE = Sr, Eu, Ba) systems are reported. Sr₂SiP₄ and Eu₂SiP₄, the first members of their respective ternary systems, are isostructural to previously reported Ba₂SiP₄ and crystallize in the noncentrosymmetric I4 2d (no. 122) space group. Ba₄Si₃P₈ crystallizes in the new structure type, in P2₁/c (no. 14) space group, mP‐120 Pearson symbol, Wyckoff sequence e³⁰. In the crystal structures of Sr₂SiP₄ and Eu₂SiP₄ all SiP₄ tetrahedral building blocks are connected via formation of P–P bonds forming a three‐dimensional framework. In the crystal structure of Ba₄Si₃P₈, Si‐P tetrahedral chains formed by corner‐sharing, edge‐sharing, and P–P bonds are surrounded by Ba cations. This results in a quasi‐one‐dimensional structure. Electronic structure calculations and UV/Vis measurements suggest that the AE₂SiP₄ (AE = Sr, Eu, Ba) are direct bandgap semiconductors with bandgaps of ca. 1.4 eV and have potential for thermoelectric applications.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 581) Tetrabariumtriphosphid,Ba4P3: Darstellung und Kristallstruktur

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 58. Tetrabariumtriphosphide, Ba₄P₃: Preparation and Crystal Structure Ba₄P₃ is obtained from the elements in the molar ratio 4:3 or by reaction of Ba₃P₂ and Ba₅P₄ in the molar ratio 1:1 (steel ampoules with inner corundum crucibles; 1 490 K). The greyish black, easily hydrolysing compound crystallizes in a new structure type oP56. The structure shows two crystallographically independent dumbbells P₂^4? (d(P? P) = 225 and 232 pm) and isolated ions P^3? corresponding to (Ba²⁺)₈(P₂^4?)₄(P^3?)₄. The partial structure of the Ba atoms forms a complex network of trigonal prisms with tetrahedral and square pyramidal holes, as well as polyhedra with 14 faces (CN 10) which are icosahedron derivatives. The P^3? anions center trigonal prisms and the 14 face polyhedron. The P-atoms of the P₂^4? dumbbells center neighboring trigonal prisms with common square faces. (Pbam (no. 55); a = 1 325.4(2) pm, b = 1 256.2(2) pm, c = 1 127.3 pm; Z = 8).     

Sr2(OLi2Sr4)[CrN4]2, ein Nitridochromat(VI)‐Oxid mit Sauerstoff in tetragonal‐bipyramidaler Koordination durch Lithium und Strontium

Sr₂(OLi₂Sr₄)[CrN₄]₂, a Nitridochromate(VI)‐Oxide with Oxygen in Tetragonal‐Bipyramidal Coordination by Lithium and Strontium Green gleaming crystals of Sr₂(OLi₂Sr₄)[CrN₄]₂ were prepared by reaction of Li, Sr and CrN/Cr₂N (approximate 1 : 1 mixture) with flowing nitrogen at 900 °C (molar overall composition Li : Sr : Cr = 6 : 1 : ∼3). The oxygen content results from a leak in the gas supply. The crystal structure was determined by single crystal methods (triclinic; P1; a = 615.87(9) pm, b = 682.50(10) pm, c = 754.30(8) pm, α = 82.302(14)°, β = 75.197(10)°, γ = 70.133(13)°; Z = 1) and contains distorted tetragonal bipyramids (OLi₂Sr₄)⁸⁺ and [Cr^VIN₄]^6–‐tetrahedra besides Sr²⁺.     

Ba11KX7O2 (X  P,As): Two Novel Zintl Phases with infinite chains of oxygen centered Ba6 octahedra,isolated X3− and dimeric X24− anions

Reactions of “BaX” (X ? P, As) with Ba, K and BaO in tantalum tubes at 900–1000°C yielded black, very air- and moisture-sensitive crystals of Ba₁₁KP₇O₂ and isotypic Ba₁₁KAs₇O₂ which were characterized by EDX and X-ray diffraction (orthorhombic, Fddd, Z = 8; a = 1069.9(1), b = 1514.3(2), c = 3164.6(4) pm and a = 1087.8(2), b = 1542.3(2), c = 3232.4(4) pm, respectively). The structure contains infinite zigzag chains, [Ba₄Ba_2/2O], of oxygen-centered, corner-sharing Ba₆ octahedra along [100]. They are connected by linear strings built of alternating isolated X atoms and X₂ dimers to form layers parallel to (001). While the isolated X atoms are surrounded by eight Ba forming a distorted cube, the X₂ dimers center a Ba₁₂ polyhedron which is comprised of a pair of face-sharing Ba square antiprisms. This results in a cube–antiprism-antiprism-cube sequence of face-sharing Ba polyhedra. Additional X atoms function as spacers between the layers and connect them along [001]. Two atom positions are statistically occupied by Ba and K, and the formula may be written as Ba²⁺₁₁K⁺X^3?₅(X₂)^4?O^2?₂ according to the Zintl-Klemm concept.     

M(SCN)2 (M = Eu,Sr, Ba): Kristallstruktur,thermisches Verhalten,Schwingungsspektroskopie

M(SCN)₂ (M = Eu, Sr, Ba): Crystal Structure, Thermal Behaviour, Vibrational Spectroscopy Single crystals of M(SCN)₂ (M = Eu, Sr, Ba) have been obtained via metathesis of NaSCN and MCl₂ (M = Eu, Sr, Ba) at 340 °C. The isotypic crystal structures of the thiocyanates M(SCN)₂ (C2/c, Z = 4, Eu: a = 979.3(2), b = 660.8(1), c = 815.7(2) pm, β = 91.58(3)°, R_all = 0.0245, Sr: a = 985.5(2), b = 662.9(2), c = 819.6(2) pm, β = 91.29(3)°, R_all = 0.0435, Ba: a = 1018.8(2), b = 687.2(1), c = 852.2(1) pm, β = 92.43(2)°, R_all = 0.0392) contain alternating layers of M²⁺ and SCN^–. According to M(SCN)_4/4(NCS)_4/4 M²⁺ is eight‐coordinated by four sulfur and four nitrogen atoms forming a square antiprism. Thermal investigations show that the compounds melt without decomposition. Vibrational spectroscopic investigations are presented and discussed.     

Die Clusterazide M2[Nb6Cl12(N3)6]·(H2O)4—x (M = Ca,Sr, Ba)

The Cluster Azides M₂[Nb₆Cl₁₂(N₃)₆]·(H₂O)_4—x (M = Ca, Sr, Ba) The isotypic cluster compounds M₂[Nb₆Cl₁₂(N₃)₆] · (H₂O)_4—x (M = Ca (1) , M = Sr (2) and M = Ba (3) ) have been synthesized by the reaction of an aequeous solution of Nb₆Cl₁₄ with M(N₃)₂. 1 , 2 and 3 crystallize in the space group Fd3¯ (No. 227) with the lattice constants a = 1990.03(23), 2015.60(12) and 2043, 64(11) pm, respectively. All compounds contain isolated 16e— clusters whose terminal positions are all occupied by orientationally disordered azide ligands.     

Ein neues Bleistrontiumferrat(III): Die Kristallstruktur der Phase Pb4Sr2Fe6O15

A New Lead Strontium Ferrate(III): The Crystal Structure of the Phase Pb₄Sr₂Fe₆O₁₅ At orthorhombic single crystals of Pb₄Sr₂Fe₆O₁₅ (a = 568.73(8), b = 392.03(4), c = 2107.5(3) pm; Z = 4/3, space group Pnma) a X-ray structure determination has been performed (R₁ = 0,036 for 488 ?observed”? resp. wR₂ = 0,073 for all 643 independent reflexions). It revealed a framework of polyhedra related to perovskite, in which chains of edgesharing pyramids [FeO₅] (average Fe1? O: 197 pm; Fe1? Fe1: 305.5 pm) are linked via apices with corner-sharing [FeO₆] octahedra (Fe2? O: 201 pm). 12–fold, strongly distorted cuboctahedrally coordinated ?perovskite positions”? show mixed occupancy by 2/3 Sr + 1/3 Pb (= Sr2; Sr2? O: 287 pm). More spacy channels, running parallel to the chains of pyramids along [010] of the structure, contain lead atoms only. The double occupancy of the corresponding cages results in short distances Pb1? Pb1 (355.9 pm) and Pb1? Fe2 (314.4 pm), as well as in a very asymmetric [PbO₆] coordination (Pb1? O: 253 pm), in the opposite hemisphere of which the lone electron pair s² is supposed to be located. Details are communicated and structural relations discussed.     

Sr5[NbN4]N ‐ A Nitridoniobate(V) Nitride Containing Isolated [NbN4]7‐ Tetrahedra and Octahedral Chains 1(Sr4Sr2/2N7+)

Sr₅[NbN₄]N (transparent, red single crystals) was synthesized by reaction of Sr2N with Nb under nitrogen at ambient pressure and 1223 K. The crystal structure was solved and refined in the space group Pbcm (no. 57), Z = 4, with lattice constants a = 646.6(3) pm, b = 1792.5(9) pm, c = 729.8(4) pm, and R = 0.019, wR² = 0.034. The crystal structure contains both isolated tetrahedra [NbN₄]^7‐ as well as chains of corner sharing octahedra 1(Sr₄Sr_2/2N⁷⁺). Strontium is irregularly coordinated by nitrogen (CN = 4 ‐ 6, Sr‐N: 252.3(4) ‐ 340.8(3) pm); nitrogen is located in a distorted octahedral environment by strontium and niobium (Nb‐N: 194.5(4) ‐ 199.2(2) pm). By formal reduction of the structural building units to their centers a close structural relationship to both the NiAs and the CaSi type structure is evident.     

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.     

Die Kristallstruktur von BaHg(CN)4 · 4 Pyridin

Crystal Structure of BaHg(CN)₄ · 4 Pyridine The structure of the tetragonal BaHg(CN)₄ · 4 Pyridine (space group I4 , a = 1119.4(7), c = 1 057.9(7) pm, Z = 2, d_c = 1.87 g · cm^?3) contains tetrahedral Hg(CN)₄ and bisdisphenoide Ba(NC)₄(py)₄ groups, which are linked together by Hg? CN? Ba bridges. The BaHg(CN)₄ framework consists of a 3-dimensional network of all round edge-sharing tetrahedrons. The analogous strontium compound is isotype with a = 1 108.2(9) and c = 1 035.3(14) pm.     

Zur Kenntnis der Hydrate des Typs MX2 · 1 H2O mit M = Sr,Ba und X = Cl,Br, I. Kristallstrukturen des Strontiumchlorid-Monohydrats,SrCl2 · 1 H2O,und des Strontiumbromid-Monohydrats,SrBr2 · 1 H2O

On Hydrates of the Type MX₂ · 1 H₂O with M = Sr, Ba and X = Cl, Br, I. Crystal Structures of Strontium Chloride Monohydrate, SrCl₂ · 1 H₂O, and Strontium Bromide Monohydrate, SrBr₂ · 1 H₂O The structures of SrCl₂ · 1 H₂O, orthorhombic, Pnma, a = 1088.1(1), b = 416.2(1), c = 886.4(1) pm, Z = 4, d_c = 2.92 Mg m^?3, R = 0.052 for 755 reflections, and of SrBr₂ · 1 H₂O, orthorhombic, Pnma, a = 1146.4(1), b = 429,5(1), c = 922.9(1) pm, Z = 4, d_c = 3.88 Mg m^?3, R = 0.056 for 762 reflections have been determined from a Patterson synthesis and refined by Fourier and Least Squares methods. The structure consists of [SrX₂ = H₂O]_n-layers normal to [100] and Sr? H₂O? Sr? H₂O-chains parallel [010]. The Sr? O distances are 265.1(3) pm, SrCl₂ · 1 H₂O, and 265.9(4) pm, SrBr₂ · 1 H₂O. The shortest Sr? Cl and Sr? Br distances (298.9(1) and 315.3(1) pm) are within the layers. The environment of oxygen and strontium is a distorted tricapped trigonal prism. The orientation of the water molecules has been determined from vibrational spectroscopic measurements. The hydrogen atoms H₁ and H₂ form bifurcated hydrogen bonds of different strength to neighbouring halide ions. The corresponding O···X distances are 331.9(4) and 320.2(4) pm, SrCl₂ · 1 H₂O, and 340.8(4) and 333.8(4) pm, SrBr₂ · 1 H₂O. The other O? X distances are between 310.3(5) and 323.7(5) pm, SrCl₂ · 1 H₂O, and 323.5(5) and 333.2(6) pm, SrBr₂ · 1 H₂O.     

Synthese und Struktur von Ba10[Ti4N12], ein ternäres Nitrid mit vierkernigen cyclischen Nitridotitanat-Ionen

Synthesis and Structure of Ba₁₀[Ti₄N₁₂], a Ternary Nitride with Tetranuclear Cyclic Nitridotitanate Ions Ba₁₀[Ti₄N₁₂] results from the reaction of Ba₃N₂, TiN, and N₂ at 980°C. It crystallizes in the triclinic space group P1 with the lattice parameters a = 644.3(4); b = 942.9(7); c = 966.9(7) pm, α = 106.37(4)°; β = 102.22(4)°; γ = 108.56(4)°, Z = 1. The crystal structure is built up by Ba²⁺ cations and tetranuclear cyclic nitridotitanate(IV) anions. In the anions four TiN₄ tetrahedra are each connected by two corners to form centrosymmetrical rings, which are stacked along [100] forming tubes. The Ti? N distances range from 192 to 199 pm.