Der Einfluß von Sauerstoff,Wasser, Chlor und Brom auf den Transport von Kohlenstoff in fluorhaltigen Systemen

Quaternary System ZnSe - Cr₂Se₃ - In₂Se₃ The section Zn_1-xIn_0.667xCr₂Se₄ and ZnCr_2-yIn_ySe₄ as well as some samples of compositions outside these joins of the quaternary system ZnSe Cr₂Se₃ - In₂Se₃ were studied with the help of X-ray Guinier photographs of quenched samples. Whereas no detectable amounts of chromium can be incorporated into ZnIn₂Se₄ of the thiogallate structure (MnIn₂Te₄ type) in the case of the spinel ZnCr₂Se₄ (a = 1050.0 pm) up to 21 mol % of chromium and up to 20 mol % of zinc can be substituted by indium. However, spinel type solid solutions with larger indium content (up to a = 1076 pm) are formed by coincident substitution of both zinc and chromium corresponding to Zn_1-xIn_0.667xCr_2-yIn_ySe₄ (0 < x + y < 0.6) with indium in both tetrahedral and octahedral lattice sites.     

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.     

Festkörperreaktionen in Chalkogenidsystemen. V. Verteilungsgleichgewichte zweiwertiger Übergangsmetalle in Chromthiospinell-Mischkristallen

The solid-state equilibria of the chromium thiospinel solid solutions M_xM′_1?xCr₂S₄ (M,M′ = Mn, Co, Zn, Cd), with excess binary sulfides MS and M′S or M_1?xM′_xS mixed crystals, are investigated. At 600°C the following equilibrium compositions are found: Mn_0.38Co_0.62Cr₂S₄, Mn_0.36Zn_0.64Cr₂S₄, Mn_0.64Cd_0.36Cr₂S₄, Co_0.33Zn_0.67Cr₂S₄, Co_0.68Cd_0.32Cr₂S₄, and Zn_0.75Cd_0.25Cr₂S₄. The results show that metals with small crystal radii and high tetrahedral site preference energy are preferentially incorporated into the tetrahedral sites of chromium thiospinels. With increasing temperature the composition of the quaternary spinels approach M_0.5M′_0.5Cr₂S₄. From the temperature dependence of the equilibrium constants the reaction enthalpies could be determined. The binary sulfides MS and M′S are incompletely miscible excepting the system $\text{ZnS}\text{CdS}$. At 600°C the following miscibility gaps are found: Mn_yZn_1?yS: y = 0.43 – ≈ 1.0, Mn_yCd_1?yS: y = 0.50 – >0.9, Co_yMn_1?yS: y = <0.1 – ≈ 1.0, Co_yZn_t?yS: y = 0.1 – ≈ 1.0, and Co_yCd_1?yS: y = 0.1 – ≈ 1.0. With increasing temperature the miscibility gaps, especially of the systems with CoS, get smaller. The spinel solid solutions and the $\text{ZnS}\text{CdS}$ mixed crystals obey Vegard's rule.     

Ca3Ni8In4—An Ordered Noncentrosymmetric Variant of the BaLi4 Type

The title compound was synthesized by reacting the elements in an arc-melting apparatus under purified argon and subsequent annealing at 870 K. Ca₃Ni₈In₄ was investigated using X-ray diffraction on both powders and single crystals: P6₃mc, a=898.9(1) pm, c=752.2(2) pm, wR2=0.0591, 327 F² values, and 35 parameters. This structure is an ordered, noncentrosymmetric variant of the BaLi₄ type. The nickel and indium atoms build a complex three-dimensional [Ni₈In₄] polyanion in which the calcium atoms fill distorted hexagonal channels. To a first approximation the formula may be written as (3 Ca²⁺)⁶⁺ [Ni₈In₄]⁶⁻. Within the polyanion the Ni1, Ni3, and Ni4 atoms form one-dimensional cluster units which extend in the c direction while the Ni2 atoms have only indium neighbors in a distorted tetrahedral coordination. The Ni–Ni distances in the cluster range from 241 to 266 pm. The cluster units are surrounded and interconnected by indium atoms. The group– subgroup relation from centrosymmetric BaLi₄ to noncentrosymmetric Ca₃Ni₈In₄ is presented. Chemical bonding in Ca₃Ni₈In₄ and the structural relation with Lu₃Co_7.77Sn₄, Ca₃Au_6.61Ga_4.39, and Co₂Al₅ is briefly discussed.     

Phasendiagramm des quasibinären Systems NiCr2S4–NiGa2S4, Kristallstruktur des NiGa2S4

Phase Relationship of the Quasibinary System NiCr₂S₄? ;NiGa₂S₄, Crystal Structure of NiGa₂S₄ The quaternary system NiCr_2–2xGa_2xS₄ was studied with the help of X-ray powder Guinier photographs of quenched samples. The crystal structure of ternary NiGa₂S₄, not found formerly, was determined using single crystal data. The structure (trigonal space group P3 m1, Z = 1, a = 362.49(2), c = 1199.56(5) pm) consists of hexagonal close-packed sulfur with Ni and Ga in one fourth of the octahedral and tetrahedral holes, respectively (FeGa₂S₄ type). The S? ;S distance of the S? ;Ni? ;S layered units is unusually small, vic. 321.1 pm. The infrared spectrum of NiGa₂S₄ and a group theoretical treatment of the FeGa₂S₄ type lattice modes are given. Up to 20 mol % Ga of the layered NiGa₂S₄ can be substituted by Cr whereby Ni is possibly transfered from octahedral to tetrahedral sites. The phase width of monoclinic Cr₃S₄ type NiCr₂S₄ is very small possibly due to the metal-metal interaction in this NiAs defect structure. In the range 0.18 ? x ? 0.35 quaternary spinel type mixed crystals are formed.     

Züchtung und röntgenographische Untersuchung von Einkristallen der Thiosilicate (Mn,Mg)2SiS4, (Mn,Fe)2SiS4 und (Mg,Fe)2SiS4 mit Olivinstruktur

Crystal Growth and Structure of Olivine Type Compounds (Mn, Mg)₂SiS₄, (Mn,Fe)₂SiS₄ and (Mg,Fe)₂SiS₄ Single crystals of (Mn, Mg)₂SiS₄, (Mn,Fe)₂SiS₄ and (Mg,Fe)₂SiS₄ were obtained by chemical transport reactions. Characterization of the crystals was done by electron microprobe analysis and X-ray methods. The compounds have the olivine structure with space group Pnma. Cell dimensions are a = 1267.6(1), b = 743.0(2), c = 592.7(2) pm for Mn_1,4Mg_0,6SiS₄, a = 1265.1(4), 736.1(2), c = 589.9(3) pm for Mn_1,4Fe_0,6SiS₄ and a = 1258.6(7), b = 732.9(3), c = 587.0(3) pm for Mg_1,14Fe_0,86SiS₄. Crystal structure refinement yielded different distributions of the two metal cations on the octahedral sites of the olivine structure: while Mn²⁺ and Mg²⁺ are evenly distributed over the M(1) and M(2) positions in Mn_1,4Mg_0,6SiS₄, the M(1) position is enriched in Fe²⁺ relative to M(2) in Mg_1,14Fe_0,86SiS₄.     

Struktur und magnetische Eigenschaften von Cs2Mn3S4 und Cs2Co3S4

Structure and Magnetic Properties of Cs₂Mn₃S₄ and Cs₂Co₃S₄ The atomic arrangements of the isotypic compounds Cs₂Mn₃S₄ and Cs₂Co₃S₄ were determined by X-ray investigations on single crystals (space group Ibam, Z = 4). To interprete the magnetic properties of Cs₂Mn₃S₄ mixed crystals of the series Cs₂(Mn_xZn_1-x)₃S₄ have been examined. Additionally neutron diffraction experiments were carried out and yielded the spin structures of Cs₂Mn₃S₄ and Cs₂Co₃S₄ (Shubnikov space group Ibam'). The deviations of the magnetic moments from those expected for high-spin d⁵ ions are explained by means of crystal field calculations.     

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.     

BiGaIn2S6 – Synthese,Struktur und Eigenschaften

BiGaIn₂S₆ – Synthesis, Structure, and Properties The novel compound BiGaIn₂S₆ was obtained in the quaternary system Bi–Ga–In–S. BiGaIn₂S₆ forms red transparent platelets and exhibits a range of homogeneity between BiGa₁In₂S₆ and BiGa_0.8In_2.2S₆. The compound is a semiconductor with E_g(opt.) = 1.9 eV. – BiGaIn₂S₆ crystallizes monoclinically forming a new structure type (a = 1112.0 pm, b = 380.6 pm, c = 1228.0 pm, β = 116.30°, Z = 2, space group P2₁/m, no. 11). The S atoms form strongly corrugated 2 D fragments of the (hc)₂ sphere packing type. The In atoms occupy octahedral holes (d(In–S) = 262 pm) and the Ga atoms tetrahedral holes (d(Ga–S) = 234 pm) inside the 2 D-layers. The Bi atoms on the top of trigonal BiS₃ pyramids (d(Bi–S) = 265 pm) are at the periphery of the layers and have four additional S ligands from the neigbouring layer at much larger distances (d(Bi–S) = 319 pm). – The bonding of a Bi^III sulfide is analyzed for the first time by the Electron Localization Function (ELF).     

Strukturuntersuchungen an InGaSe2 und InGaTe2

Structure Investigations on InGaSe₂ and InGaTe₂ The preparation of the compounds InGaSe₂ and InGaTe₂ is reported. X-ray structure investigations at different temperatures for both compounds using their black single crystals with metallic lustre proof them to crystallize in the TlSe-type (InGaSe₂: a = 805.1(1) pm, c = 631.7(4) pm; InGaTe₂: a = 841.2(2) pm, c = 687.5(3) pm; Z = 4; I4/mcm), which is characterized by one-dimensional linear chains of edge-sharing GaSe₄-tetrahedra parallel to the c-axis of the tetragonal unit cell. The indium-indium distances within the indium chains running parallel to c are not commensurate with the tetrahedral chains in the case of InGaSe₂ giving rise to a pronounced incommensurate superstructure with complicated pattern. This is the reason why the indium positions for this compound, in contrast to InGaTe₂, do not correspond to the TlSe-type and cannot be resolved in the course of a conventional structure analysis because their electron density is nearly homogeneously smeared out along the indium chains.     

Syntheses and Structure of Gd<Subscript>3</Subscript>Rh<Subscript>1.940(7)</Subscript>In<Subscript>4</Subscript>

Summary. The gadolinium–rhodium–indide Gd₃Rh_1.940(7)In₄ was prepared by arc-melting of the elements and subsequent annealing in a corundum crucible in a sealed silica tube. Gd₃Rh_1.940(7)In₄ adopts the hexagonal Lu₃Co_1.87In₄ type, space group , a = 781.4(5), c = 383.8(3) pm, wR2 = 0.0285, BASF = 0.375(1) (merohedric twinning via a twofold axis (xx0)), 648 F² values, 22 variables. The structure is derived from the well known ZrNiAl type through an ordering of rhodium and indium atoms on the Ni2 sites. The Rh/In ordering forces a reduction of the space group symmetry from to , leading to merohedric twinning for the investigated crystal. The Rh1 site has an occupancy of only 94.0(7)%. The investigated crystal had a composition Gd₃Rh_1.940(7)In₄. The main geometrical motif are three types of centered, tricapped trigonal prisms, i.e., [Rh1In2₆Gd₃], [Rh2Gd₆In2₃], and [In1Gd₆In2₃]. The shortest interatomic distances occur for Rh–In (276–296 pm) followed by In–In (297 pm). Together, the rhodium and indium atoms build up a three-dimensional [Rh_1.940(7)In₄] network, in which the gadolinium atoms fill slightly distorted pentagonal channels. The crystal chemistry of Gd₃Rh_1.940(7)In₄ is discussed on the basis of a group-subgroup scheme.     

Characterization of Mixed Crystals in the System Cu2MnxCo1−xGeS4 and Investigations of the Tetrahedra Volumes

In a series of investigations on normal tetrahedral compounds we present mixed crystals in the system Cu₂Mn_xCo_1?xGeS₄ (0 < x < 1) and an inspection of their tetrahedra volumes. Cu₂CoGeS₄ crystallizes tetragonal in a stannite type structure, Cu₂MnGeS₄ crystallizes orthorhombic in the wurtzstannite structure type. The crystal structures of Cu₂CoGeS₄ and Cu₂Mn_0.68Co_0.32GeS₄ were refined from single crystal diffraction data. The refinement of Cu₂CoGeS₄ converged to R = 0.0547 and wR2 = 0.0847 for 299 unique reflections. The refinement of Cu₂Mn_0.68Co_0.32GeS₄ converged to R = 0.0481 and wR2 = 0.0877 for 1556 unique reflections. From these data the tetrahedra volumes of the end members and of Cu₂Mn_0.68Co_0.32GeS₄ are calculated. In Cu₂CoGeS₄ tetrahedra [MS₄] are similar in size. In contrast, the differences of the volumes of the polyhedra [MS₄] in the orthorhombic wurtzite superstructure type compounds Cu₂MnGeS₄ and Cu₂Mn_0.68Co_0.32GeS₄ are significant (M = Cu, Mn, (Mn_0.68Co_0.32), Co, Ge). From x = 0 to x = 0.5 the tetragonal structure type dominates while from x = 0.7 to the Cu₂MnGeS₄ end member the products crystallize in the orthorhombic structure type. Melting points of the mixed crystals decrease linearly with increasing manganese content.     

Phase relationships in the systems MSCr2S3In2S3 (M = Co,Cd, Hg)

The phase diagrams of the quaternary systems MSCr₂S₃In₂S₃, with M = Co, Cd, and Hg, were studied with the help of X-ray powder photographs of quenched samples, high-temperature X-ray diffraction patterns, DTA and TG measurements, and far-infrared spectra. Because indium sulfides do react with silica tubes, alumina crucibles must be used for annealing the samples. Complete series of mixed crystals are formed among the spinel-type compounds MCr₂S₄, MIn₂S₄ (M = Cd, Hg), and In₂S₃. HgIn₂S₄ is decomposed at temperatures above 300°C. In the sections CoCr₂S₄CoIn₂S₄ and CoCr₂S₄In₂S₃ relatively large miscibility gaps exist due to the change from normal to inverse spinel structure. But the interchangeability of both systems increases with increasing temperature, and at temperatures above 1000°C, complete series of solid solutions are formed, which can be quenched to ambient temperature. Superstructure ordering like that of ordered α-In₂S₃ has been found in the In-rich region of the MIn₂S₄In₂S₃ solid solutions. The unit cell dimensions of all stoichiometric and phase boundary compounds, e.g., Cd_1.15In_1.9S₄, including the chromium spinels MCr₂S₄ (M = Mn, Zn) and ZnCr₂Se₄, are given and discussed in terms of possible deviations from stoichiometry.     

IR-Spektroskopische und Röntgenographische Untersuchungen an Thiospinellmischkristallen

The effect of the tetrahedral and octahedral coordinated metal and nonmetal atoms on the vibrational spectra of spinels is studied by investigation of mixed crystals and defect spinels like In₂S₃. The following solid solutions of chromium thiospinels and indium sulfides have been prepared and investigated by X-rays and FIR-spectroscopy: Hg_xZn_{1 ? x}Cr₂S₄ (I), ZnIn_xCr_{2 ? x}S₄ (II), CdIn_xCr_{2 ? x}S₄ (III), ZnCr₂Se_xS_{4 ? x} (IV), α-In₂S₃ (V), β-In₂S₃ (VI) and Cr_xIn_{2 ? x}S₃ (VII). The lattice constants of (I), (III), (IV) and (VII) obey Vegard's rule. (III) has a miscibility gap between x = 0.3 and x = 1.8. The spectroscopic behavior of the solid solutions (all the four peaks of the spinel spectra split or shift) can not be interpreted on the basis of internal vibrations of different coordination polyhedra. An explanation of the additional peaks in the spectra of the mixed crystals is given according to order of the atoms or distortion of the spinel structure.     

Gd3Pt4In12 and Tb3Pt4In12 — New Ternary Indides with Condensed Distorted [PtIn6] Trigonal Prisms

The ternary indium compounds Gd₃Pt₄In₁₂ and Tb₃Pt₄In₁₂ were synthesized from an indium flux. Arc‐melted precursor alloys with the starting compositions ∼GdPtIn₄ and ∼TbPtIn₄ were annealed with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. Both compounds were investigated by X‐ray powder diffraction: a = 990.5(1), c = 1529.5(3) pm for Gd₃Pt₄In₁₂ and a = 988.65(9), c = 1524.0(1) pm for Tb₃Pt₄In₁₂. The structure of the gadolinium compound was solved and refined from single crystal X‐ray data: P3¯m1, wR2 = 0.0470, 1469 F² values and 62 variable parameters. Both crystallographically different platinum sites have a slightly distorted trigonal prismatic indium coordination. These [PtIn₆] prisms are condensed via common edges and corners forming a complex three‐dimensional [Pt₁₂In₃₂] network. The gadolinium, In1 and In7 atoms fill cavities within this polyanion. Tb₃Pt₄In₁₂ is isotypic with the gadolinium compound.     

Strukturverfeinerung und magnetische Messungen an Mn2SnS4

Structure Redetermination and Magnetic Studies on Mn₂SnS₄ The crystal structure of Mn₂SnS₄ was redetermined by single crystal and powder X-ray studies. It has a deficient NaCl superstructure crystallizing in the orthorhombic space group Cmmm proposed by Wintenberger and Jumas in 1980 (Z = 2, a = 740.7(1), b = 1047.5(1) and c = 366.7(2) pm, R_f = 1.4% for 266 unique reflections with I > 0σ₁). Some additional reflections, which are not compatible with this cell, can be refined assuming formation of twinned trilling crystals. Mn₂SnS₄ undergoes antiferromagnetic ordering below 160 K. The effective magnetic moment μ_eff of Mn²⁺ is 5.92 B.M. The IR and Raman spectra display 5 and 3 bands in the range 150–320 cm^?1, respectively.     

Neue Phosphor-verbrückte Übergangsmetallcarbonyl-Komplexe Die Kristallstrukturen von [Re2(CO)7(PtBu)3], [Co4(CO)10(PtBu)2], [Ir4(CO)6(PtBu)6] und [Ni4(CO)10(PiPr)6]

New Phosphorus-bridged Transition Metal Carbonyl Complexes. The Crystal Structures of [Re₂(CO)₇(P^tBu)₃], [Co₄(CO)₁₀(P^tBu)₂], [Ir₄(CO)₆(P^tBu)₆], and [Ni₄(CO)₁₀(PⁱPr)₆], (P^tBu)₃ reacts with [Mn₂(CO)₁₀], [Re₂(CO)₁₀], [Co₂(CO)₈] and [Ir₄(CO)₁₂] to form the multinuclear complexes [M₂(CO)₇(P^tBu)₃] (M = Re ( 1 ), Mn ( 5 )), [Co₄(CO)₁₀(P^tBu)₂] ( 2 ) and [Ir₄(CO)₆(P^tBu)₆] ( 3 ). The reaction of (PⁱPr)₃ with [Ni(CO)₄] leads to the tetranuclear cluster [Ni₄(CO)₁₀(PⁱPr)₆] ( 4 ). The complex structures were obtained by X-ray single crystal structure analysis: ( 1 : space group P1 (Nr. 2), Z = 2, a = 917.8(3) pm, b = 926.4(3) pm, c = 1 705.6(7) pm, α = 79.75(3)°, β = 85.21(3)°, γ = 66.33(2)°; 2 : space group C2/c (Nr. 15), Z = 4, a = 1 347.7(6) pm, b = 1 032.0(3) pm, c = 1 935.6(8) pm, β = 105.67(2)°; 3 : space group P1 (Nr. 2), Z = 4, a = 1 096.7(4)pm, b = 1 889.8(10)pm, c = 2 485.1(12) pm, α = 75.79(3)°, β = 84.29(3)°, γ = 74.96(3)°; 4 : space group P2₁/c (Nr. 14), Z = 4, a = 2 002.8(5) pm, b = 1 137.2(8) pm, c = 1 872.5(5) pm, β = 95.52(2)°).     

Zur Oktaederstreckung an A2BO4-Verbindungen: SrNdMnO4 und SrNdCrO4

About the Octahedra Elongation on A₂BO₄ Compounds: SrNdMnO₄ and SrNdCrO₄ Single crystals of SrNdMnO₄ (I) and SrNdCrO₄ (II) were prepared. The X-ray investigation of (I) and (II) lead to the tetragonal space group D? I4/mmm; lattice constants: (I) a = 377.7; c = 1296 pm; (II) a = 384.2; c = 1233.8 pm. The elongation of the oxygen octahedra surrounding Mn³⁺ and Cr³⁺ are discussed.