Refinement of the Crystal Structure of Sr3Hg2

Mixtures of strontium and mercury in molar ratios of 7:3 have been annealed for 20 days at 520°C. From the pure product Sr₃Hg₂ single crystals have been obtained. Sr₃Hg₂ crystallizes in the U₃Si₂ type of structure (space group P4/mbm); the cell constants are a = 8.883 (2) Å and c = 4.553(1) Å. All of the Hg atoms are involved in Hg₂ dumbbells with Hg? Hg distances of 3.41 Å.     

Struktur‐ und magnetochemische Untersuchungen an Ba5Mn3F19 und verwandten Verbindungen AII5MIII3F19

Structural and Magnetochemical Studies of Ba₅Mn₃F₁₉ and Related Compounds A^II₅M^III₃F₁₉ Single crystal structure determinations by X‐ray methods were performed at the following compounds, crystallizing tetragonally body‐centred (Z = 4): Sr₅V₃F₁₉ (a = 1423.4(2), c = 728.9(1) pm), Sr₅Cr₃F₁₉ (a = 1423.5(2), c = 728.1(1) pm), Ba₅Mn₃F₁₉ (a = 1468.9(1), c = 770.3(1) pm, Ba₅Fe₃F₁₉ (a = 1483.5(1), c = 766.7(1) pm), and Ba₅Ga₃F₁₉ (a = 1466.0(2), c = 760.1(2) pm). Only Ba₅Mn₃F₁₉ was refined in space group I4cm (mean distances for elongated octahedra Mn1–F: 185/207 pm equatorial/axial; for compressed octahedra Mn2–F: 199/182 pm), the remaining compounds in space group I4/m. In all cases the octahedral ligand spheres of the M1 atoms showed disorder, the [M1F₆] octahedra being connected into chains in one part of the compounds and into dimers in the other. The magnetic properties of the V, Cr and Mn compounds named above and of Pb₅Mn₃F₁₉ and Sr₅Fe₃F₁₉ as well were studied; the results are discussed in context with the in part problematic structures.     

Über die Synthese von Erdalkalimetalldihalogeniden und die Strukturen von Ca3Br2CBN und Sr3Cl2CBN

On the Synthesis of Alkaline-Earth Dihalides and the Structures of Ca₃Br₂CBN and Sr₃Cl₂CBN The reaction of alkaline-earth carbonates with ammonium chloride or bromide yields alkaline-earth dihalides at relatively low temperatures (300°C). Ca₃Br₂CBN and Sr₃Cl₂CBN were synthesized in sealed niobium containers at 950°C from the metal, its dihalide, boron nitride and graphite. The crystal structure of Sr₃Cl₂CBN was refined from single crystal data. Sr₃Cl₂CBN crystallizes isotypic with Ca₃Cl₂CBN in the orthorhombic space group Pnma (No. 62) with a = 1448.4(2) pm b = 405.46(5) pm, c = 1170.0(1) pm. The lattice constants of Ca₃Br₂CBN and Sr₃Cl₂CBN were determined by orthorhombic indexing of the powder patterns (Ca₃Br₂CBN: a = 1444.3(2) pm, b = 390.64(6) pm, c = 1139.2(2) pm; Sr₃Cl₂CBN: a = 1444.0(4) pm, b = 405.27(8) pm, c = 1167.8(2) pm). There was no success in preparing homologues with Barium.     

Polykationische Hg‐Pnictid‐Gerüste mit einer neuen Füllungsvariante in den Strukturen von Hg3As2TlCl3 und Hg3Sb2TlBr3

Polycationic Hg‐Pnictide Frameworks with a Novel Kind of Filling in the Structures of Hg₃As₂TlCl₃ and Hg₃Sb₂TlBr₃ Hg₃As₂TlCl₃ and Hg₃Sb₂TlBr₃ were prepared from mixtures of Hg₂X₂, HgX₂ (X = Cl, Br), As or Sb and Tl in sealed evacuated glass ampoules in temperature gradients 330 °C → 290 °C for Hg₃As₂TlCl₃ (red, transparent crystals) and 290 °C → 260 °C for Hg₃Sb₂TlBr₃ (black crystals). The structures of the diamagnetic compounds were determined based on single crystal X‐ray diffraction data. Both compounds crystallize isotypically in the orthorhombic space group Pbcm with Z = 4 and the lattice constants a = 629.2(5) pm, b = 1234.1(7) pm and c = 1224.8(9) pm for Hg₃As₂TlCl₃ and a = 661.0(4) pm, b = 1311.2(9) pm and c = 1307.1(2) pm for Hg₃Sb₂TlBr₃. The structures can be described either as a cubic closest packing of As₂/Sb₂ dumb‐bells and halide anions with all octahedral interstices filled with Hg²⁺ and Tl⁺, or as a polycationic framework (Hg₃Y₂)²⁺ (Y = As, Sb) consisting of pnictide‐pnictide dumbbells each connected by six Hg atoms to a three dimensional porous arrangement. The centers of the cavities are occupied by Tl⁺ ions which are coordinated by six halide ions in distorted octahedral form. These TlX₆ octahedra share corners in all directions in the motive of the ReO₃ structure type. This new structure type shows a close relationship to the cubic family of compounds of the general formula (Hg₆Y₄)[MX₆]X (Y = As, Sb; M = Mo, Ti, Bi, Sb; X = Cl, Br). The halide ions are connected to the Hg atoms of the polycationic network and to the Tl⁺ ions. Extended Hueckel calculations were used to explain the bonding character of the thallium–halide and mercury–halide bonds.     

Zur Kenntnis der Struktur von Sr3(BN2)2

On the Structure of Sr₃(BN₂)₂ The structure of Sr₃(BN₂)₂ was determined on single-crystal X-ray data collected with a four-circle diffractometer. Sr₃(BN₂)₂ crystallizes in the cubic space group Im3 m (no. 229) with a = 764.56(3) pm and Z = 3. The structure contains linear BN^3?₂ ions with a B? N bond length of 135.8(6) pm. The straight forward synthesis employing metal nitrides plus boron nitride yielded crystalline powders of M₃(BN₂)₂ (M = Ca, Sr) at 1100°C (5 days). Cubic indexing of guinier patterns gave a = 765.8(1) pm for M = Sr and a = 734.7(2) pm for M = Ca. The structure refinement on a single crystal of Sr₃(BN₂)₂ revealed that one strontium site (2a; 0, 0, 0) is occupied by only about 50%. It has been tried to fully occupy this site with an alkali metal (A) to obtain ASr₄(BN₂)₃ (Z = 2). Reactions with A = Na yielded crystalline powders. Cubic indexing of the guinier pattern analogous to that of Sr₃(BN₂)₂ gave a = 754.2(1) pm.     

Polysulfonylamine. XXXVII. Darstellung von Quecksilberdimesylamiden. Kristall- und Molekülstrukturen von Hg[N(SO2CH3)2]2, Hg[{N(SO2CH3)2}2(DMSO)2] und Hg[{N(SO2CH3)2}2(HMPA)]

Polysulfonyl Amines. XXXVII. Preparation of Mercury Dimesylamides. Crystal and Molecular Structures of Hg[N(SO₂CH₃)₂]₂, Hg[{N(SO₂CH₃)₂}₂(DMSO)₂], and Hg[{N(SO₂CH₃)₂}₂(HMPA)] Hg[N(SO₂CH₃)₂]₂ ( 1 ) and Hg₂[N(SO₂CH₃)₂]₂ ( 2 a ) are formed as colourless, sparingly soluble precipitates when solutions of Hg(NO₃)₂ or Hg₂(NO₃)₂ in dilute nitric acid are added to an aqueous HN(SO₂CH₃)₂ solution. By a similar reaction, Hg₂[N(SO₂C₆H₄ ? Cl? 4)₂]₂ is obtained. 1 forms isolable complexes of composition Hg[N(SO₂CH₃)₂]₂ · 2 L with L = dimethyl sulfoxide (complex 3 a ), acetonitrile, dimethyl formamide, pyridine or 1,10-phenanthroline and a (1/1) complex Hg[N(SO₂CH₃)₂]₂ · HMPA ( 4 ) with hexamethyl phosphoramide. Attempted complexation of 2 a with some of these ligands induced formation of Hg⁰ and the corresponding Hg^II complexes. Crystallographic data (at -95°C) are for 1: space group 14₁/a, a = 990.7(2), c = 2897.7(8) pm, V = 2.844 nm³, Z = 8, D_x = 2.545Mgm^?3; for 4a: space group P1 , a = 767.8(2), b = 859.2(2), c = 925.2(2)pm α = 68.44(2), β = 86.68(2), γ = 76.24(2)°, V = 0.551nm³, Z = 1, D_x = 2.113 Mgm^?3; for 4: space group P2₁/c, a = 1041.3(3), b = 1545.4(3), c = 1542.5(3) pm, β = 100.30(2)°, V = 2.474nm³, Z = 4, D_x = 1.944Mgm³. The three compounds form molecular crystals. The molecular structures contain a linear or approximately linear, covalent NHgN moiety; the Hg? N distances and N? Hg? N angles are 206.7(4) pm and 176.3(2)° for 1, 207.2(2) pm and 180.0° for 3a, 205.7(4)/206.7(4) pm and 170.5(1)° for 4. In the complexes 3a and 4, the 0-ligands are bonded to the Hg atoms perpendicularly to the N? Hg? N axes, leading in 3a to a square-planar trans-(N₂O₂) coordination with Hg? 0 261.2(2) pm and N? Hg? O 92.3(1)/87.7(1)°, in 4 to a slightly distorted T-shaped (N₂O) geometry with Hg? 0 246.2(4)pm and N? Hg? 0 96.7(1)/92.0(1)°. In all three structures, the primary coordination is extended to a severely distorted (N₂O₄) hexacoordination by the appropriate number of secondary, inter- and/or intramolecular Hg…?0 inter-actions (0 atoms from sulfonyl groups, Hg…?O distances in the range 280—300pm). The intramolecular Hg…?O interactions give rise to nearly planar four-membered [HgNSO] rings. The molecule of 1 has a two-fold axis through the bisector of the N? Hg? N angle, the molecule of 3a an inversion center at the Hg atom. The molecule of 4 has no symmetry.     

Pentaazadienido-Komplexe von Zink,Cadmium und Quecksilber Die Kristallstruktur von [Cd(EtOC6H4-N5-C6H4OEt)2(py)2] und [Hg(tol-N5-tol)2(py)]

Pentaazadienido Complexes of Zinc, Cadmium, and Mercury. The Crystal Structure of [Cd(EtOC₆H₄-N₅-C₆H₄OEt)₂(py)₂] and [Hg(tol-N₅-tol)₂(py)] The pentaazadienido complexes [M(EtOC₆H₄N₅C₆H₄OEt)₂] (M = Zn ( 1 ), Cd ( 2 )) are formed by the reaction of [M(NH₃)₄]²⁺ with [EtOC₆H₄N₅C₆H₄OEt]^? in aqueous ammonia. 2 crystallizes from pyridine as [Cd(EtOC₆H₄N₅C₆H₄OEt)₂py₂] ( 3 ) with the triclinic space group P1 and a = 937.2(2); b = 1422.7(2); c = 2085.5(2) pm; α = 75.28(1)°; β = 94.74(1)°; γ = 99.75(1)°; Z = 2. The central Cd²⁺ ion of 3 exhibits an octahedral coordination by two pyridine ligands in cis arrangement and two (N1, N3)-²⁺ chelating pentaazadienide ions. The reaction of [HgI₄]² with the 1,5-di(tolyl)pentaazadienide anion in aqueous ammonia affords [Hg(p-tol-N₅-tol)₂] ( 4 ), which crystallizes from pyridine in form of [Hg(tol-N₅-tol)₂py] ( 5 ) with the space group P1 and a = 1176.2(4); b = 1203.1(3); c = 1295.6(5) pm; α = 100.77(3)°; β = 110.08(3)°; γ = 94.29(2)°; Z = 2. In 5 the Hg²⁺ cation is threefold coordinated by two monodentate (N3)-η¹ pentaazadienid anions and one pyridine ligand. Within the N₅ chains of the pentaazadienid anions of 3 and 5 localized N? N double bonds are found in the positions N1? N2 and N4? N5 with distances between 125 and 129 pm.     

Präparation,Kristallstruktur und thermisches Verhalten der Quecksilber(I)phosphate α-(Hg2)3(PO4)2, β-(Hg2)3(PO4)2 und (Hg2)2P2O7

Contributions on Crystal Structures and Thermal Behaviour of Anhydrous Phosphates. XXIII. Preparation, Crystal Structure, and Thermal Behaviour of the Mercury(I) Phosphates α-(Hg₂)₃(PO₄)₂, β-(Hg₂)₃(PO₄)₂, and (Hg₂)₂P₂O₇ Light-yellow single crystals of (Hg₂)₂P₂O₇ have been obtained via chemical vapour transport in a temperature gradient (500 °C → 450 °C, 23 d) using Hg₂Cl₂ as transport agent. Characteristic feature of the crystal structure (P2/n, Z = 2, a = 9,186(1), b = 4,902(1), c = 9,484(1) Å, β = 98,82(2)°, 1228 independent of 5004 reflections, R(F) = 0,066 for 61 variables, 7 atoms in the asymmetric unit) are Hg₂²⁺-units with d(Hg1–Hg1) = 2,508 Å and d(Hg2–Hg2) = 2,519 Å. The dumbbells Hg₂²⁺ are coordinated by oxygen, thus forming polyhedra [(Hg1₂)O₄] and [(Hg2₂)O₆]. These polyhedra share some oxygen atoms. In addition they are linked by the diphosphate anion P₂O₇^4– (ecliptic conformation; ∠(P,O,P) = 129°) to built up the 3-dimensional structure. Under hydrothermal conditions (T = 400 °C) orange single crystals of the mercury(I) orthophosphates α-(Hg₂)₃(PO₄)₂ and β-(Hg₂)₃(PO₄)₂ have been obtained from (Hg₂)₂P₂O₇ and H₃PO₄ (c = 1%). The crystal structures of both modifications have been refined from X-ray single crystal data [α-form (β-form): P2₁/c (P2₁/n), Z = 2 (2), a = 8,576(3) (7,869(3)), b = 4,956(1) (8,059(3)), c = 15,436(3) (9,217(4)) Å, β = 128,16(3) (108,76(4))°, 1218 (1602) independent reflections of 4339 (6358) reflections, R(F) = 0,039 (0,048) for 74 (74) variables, 8 (8) atoms in the asymmetric unit]. In the structure of α-(Hg₂)₃(PO₄)₂ three crystallographically independent mercury atoms, located in two independent dumbbells, are coordinated by three oxygen atoms each. Thus, [(Hg₂)O₆] dimers with a strongly distorted tetrahedral coordination of all mercury atoms are formed. Such dimers are present besides [(Hg₂)O₅]-polyhedra in the less dense crystal structure of β-(Hg₂)₃(PO₄)₂ (d(Hg–Hg) = 2,518 Å). The mercury(I) phosphates are thermally labile and disproportionate between 200 °C (β-(Hg₂)₃(PO₄)₂) and 480 °C (α-(Hg₂)₃(PO₄)₂) to elemental mercury and the corresponding mercury(II) phosphate.     

Ca6GaN5 und Ca6FeN5. Verbindungen mit [CO3]2−-isosteren Anionen [GaN3]c− und [FeN3]6−

Ca₆GaN₅ and Ca₆FeN₅: Compounds Containing [CO₃]^2?-isosteric Anions [GaN₃]^6? and [FeN₃]^6? The isotypic phases Ca₆GaN₅ and Ca₆FeN₅ (hexagonal, P6₃/mem; a = 627.7(3)/ 623,7(1) pm, c = 1219.8(3)/1233.2(6) pm; Z = 2) are prepared by reaction of Ca/Ga mixtures (molar ratio 6:1) and Fe/Ca₃N₂/Ca mixtures (molar ratios from 3:1:13 to 5:2:15) with nitrogen at temperatures of 850°C and 950°C to 1100°C, respectively. The structures contain trigonal-planar anions [MN₃]^6? which are isosteric to carbonate ions (Ga? N: 195,1(28) pm; Fe? N: 177,0(15) pm). The structures are closely related to those compounds of the hydrotalcite group.     

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).     

Rb5Hg19: Eine neue,geordnete Defektvariante des BaAl4‐Strukturtyps

Rb₅Hg₁₉: A New Defect Variant of the BaAl₄ Structure Type The hitherto unknown, silver metallic, air sensitive Rb₅Hg₁₉ can be prepared directly from the elements. It crystallizes tetragonally with lattice constants a = 1156.1 pm, c = 1051.0 pm (Z = 2, space group I4/m, No. 87, melting temperature 467 K) in a new defect variant of the BaAl₄ structure type. The structure is based on distorted 4⁴ nets of Hg₄ rectangles and squares forming rectangular and square pyramids together with additional Hg atoms. The vertices of the pyramids point in alternate directions with respect to [001]. Opposite vertices show relatively short contacts d_Hg–Hg = 292.3 pm along [001]. The defect character of the Rb₅Hg₁₉ structure shows up by single Hg atoms substituting each fifth Hg–Hg group in an ordered way and serving as common vertices for two subsequent square pyramids along [001]. The replacement of Hg–Hg groups by single Hg atoms explains the vertical and horizontal distortions of the 4⁴ nets and explains the differences of the Rb coordination with respect to Ba (bicapped tetragonal hexagonprism) in the BaAl₄ type, in which a hypothetical RbHg₄ could eventually crystallize. The symmetry relations of Rb₅Hg₁₉ and α‐La₃Al₁₁ (the only defect variant of BaAl₄ except Rb₅Hg₁₉) to the aristo type BaAl₄ are discussed.     

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.     

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.     

Synthesis and Crystal Structure of Hg5Sb2I6

Mercury antimonide iodide, Hg₅Sb₂I₆, previously and erroneously reported as Hg₃Sb₂I₄ was synthesized using standard ampoule technique. A gas-phase transport reaction was applied for preparation of single crystals. Hg₅Sb₂I₆ crystallizes in the space group Pc2₁n (No. 33) with unit cell dimensions: a = 8.108(1), b = 10.702(1), c = 21.295(1) Å. Crystal structure solved using single crystal X-ray data is built of [HgSbI₃] tetrahedra and [HgSbI₂] triangles. All antimony atoms are joined into Sb₂^4? dumbbells. The structure is compared with ones containing similar Sb₂^4? dumbbells.     

Strukturen aus AIB2− und BaAl4−analogen Einheiten. I Die Verbindungen Sr4Pd5P5 und Sr2Pd3P3

Structures with AIB₂? and BaAl₄?type Units. I The Compounds Sr₄Pd₅P₅ and Sr₂Pd₃P₃ Sr₄Pd₅P₅ (Cmcm, a = 4.177(1) Å, b = 31.377(5) Å, c = 8.581(2) Å, Z = 4) und Sr₂ Pd₃P₃(Pmmm, a = 4.199(1) Å, b = 4.212(1) Å, c = 34.227(4) Å, Z = 4) have been prepared by heating the elements. Both structures contain exclusively units characteristic for the AIB_2? and BaAl₄?type. The ratio between isolated P-atoms and P₂?pairs is interpreted with an ionic splitting of the formulas.     

SrPtIn,Sr2Pt3In4, and Ca2Au3In4 – Alkaline Earth Compounds with Complex Three-Dimensional [PtIn], [Pt3In4], and [Au3In4] Polyanions

Single phase SrPtIn, Sr₂Pt₃In₄ and Ca₂Au₃In₄ were prepared by high-frequency melting of the elements in water-cooled glassy carbon crucibles. X-ray diffraction of powders and single crystals yielded Pnma, oP12, a = 758.57(9) pm, b = 451.52(6) pm, c = 846.0(2) pm, wR2 = 0.0937, 467 F² values, 20 variables for SrPtIn, P62m, hP36, a = 1465.9(2) pm, c = 448.24(6) pm, wR2 = 0.0722, 1059 F² values, 44 variables for Sr₂Pt₃In₄ and Pnma, oP36, a = 1463.6(4) pm, b = 443.23(9) pm, c = 1272.3(2) pm, wR2 = 0.0694, 1344 F² values, 56 variables for Ca₂Au₃In₄. SrPtIn adopts the TiNiSi type structure. The indium atoms have a distorted tetrahedral platinum coordination. These InPt_4/4 tetrahedra are edge- and corner-shared, forming a three-dimensional [PtIn] polyanion in which the strontium atoms are embedded. Sr₂Pt₃In₄ crystallizes with the Hf₂Co₄P₃ type structure with the more electronegative platinum atoms occupying the phosphorus sites while the indium atoms are located on the cobalt positions. Ca₂Au₃In₄ is a new site occupancy variant of the YCo₅P₃ type. Gold atoms occupy the phosphorus sites and indium the cobalt sites, but one cobalt site is occupied by calcium atoms leading to the composition Ca₂Au₃In₄. Common geometrical motifs of both structures are condensed, platinum(gold)-centered trigonal prisms formed by the alkaline earth and indium atoms. The platinum (gold) and indium atoms form complex three-dimensional [Pt₃In₄] and [Au₃In₄] polyanions, respectively. The alkaline earth cations are located in distorted hexagonal tubes.     

Darstellung und Kristallstruktur von SnTl4Se3 mit einer Anmerkung zu TlSe

Preparation and Crystal Structure of SnTl₄Se₃ with a Note on TlSe We describe the preparation and crystal structure of SnTl₄Se₃. It crystallizes as a low symmetric distorted derivative with the In₅Bi₃ type of structure, which itself should be considered as a subfamily of the Cr₅B₃ type of structure: a = 852.2(2) pm, c = 1 272.2(6) pm, c/a = 1.49, Z = 4. Short Sn? Se distances of 311 pm, and 326 pm, respectively, are obtained in [SnSe_2/2] chains running along [001]. Furthermore, short Tl? Se distances are found in quasimolecular bent moieties Tl₂Se: 300 pm, 313 pm, and 347 pm, respectively. SnTl₄Se₃ is a semiconductor. The conductivity of some closely related phases are also reported. Finally, the structure of the well known compound TlSe has been refined for the first time, in order to get some more information about Tl¹⁺? Se distances for square-antiprismatic coordinated Tl¹⁺ ions.     

Kristallstrukturuntersuchungen an den Alkali- und BariumÜbergangsmetallfluoriden RbK2Mn2F7, BaNiF4 und einer 5 : 3-Phase im System BaLiF3/NaCoF3

Crystal Structural Studies of the Alkali and Barium Transition Metal Fluorides RbK₂Mn₂F₇, BaNiF₄, and a 5 : 3-Phase of the System BaLiF₃/NaCoF₃ At single crystals of the compounds RbK₂Mn₂F₇, BaNiF₄, and of a phase 0.618 BaLiF₃/0.382 NaCoF₃ the X-ray crystal structures were refined. RbK₂Mn₂F₇ is tetragonal (a = 421.1(1), c = 2188.3(2) pm, I4/mmm, Z = 2) and belongs to the Sr₃Ti₂O₇ type. The average distances are Mn–F: 210.7 pm for the [MnF₆] octahedron and A–F: 290.6 resp. 297.1 pm for the [AF₉] resp. [AF₁₂] coordination of the mixed alkali positions (A = Rb/3 + 2 K/3). BaNiF₄ (a = 413.7(1), b = 1443.1(3), c = 578.1(1) pm, Cmc2₁, Z = 4) is of the orthorhombic BaZnF₄ type; Ni–F: 200.3 pm, Ba–F: 274.3 pm for CN6 and CN9, resp.. The phase of approximate composition 5 : 3, isolated from a 1 : 1 batch BaLiF₃/NaCoF₃, is cubic (a = 801.8(1) pm, Im3, Z = 8 AMF₃) and forms a strongly disordered perovskite super-structure, the features of which are discussed.