Untersuchungen zum System BiOBr/SeO2

Investigations on the System BiOBr/SeO₂ The section BiOBr/SeO₂ was shown to be quasibinary and include only one intermediate phase BiOBr · SeO₂ = BiSeO₃Br. The phase barogram and the phase diagram were determined by total pressure measurements and DTA. BiSeO₃Br melts peritectically at 490 ± 3 °C and forms an eutectic mixture with SeO₂ at 70 Mol.‐% SeO₂ and 210 ± 10 °C. From the chemical vapour transport of BiOBr_s with SeO_2,g and the sublimation of BiSeO₃Br_s followed the existence of BiSeO₃Br_g molecules in the vapour. The thermodynamic data of the solid and the vapour phase were derived. (Data see Inhaltsübersicht)     

Untersuchungen zum System BiOCl/SeO2

Investigations on the System BiOCl/SeO₂ The section BiOCl/SeO₂ was shown to be quasibinary one and include only one intermediate phase BiOCl · SeO₂ = BiSeO₃Cl. The phase barogram and the phase diagram were determined by total pressure measurements and DTA. BiSeO₃Cl shows on heating two transitions in crystal phase, (α → β) at 400 ± 2 °C and (β → γ) at 410 ± 3 °C. The compound melts peritectically at 417 ± 3 °C. The experiments on sublimation of BiSeO₃Cl in the temperature gradient and chemical vapour transport with SeO₂ allowed to make the conclusion on the existence of BiSeO₃Cl molecules in the vapour. Some standard thermodynamic data were determined by solution calorimetry and evaluated from the vapour pressure and chemical vapour transport rate data. (Data see Inhaltsübersicht)     

Untersuchungen zum System Bi2O3/BiI3

Investigations on the System Bi₂O₃/BiI₃ The temperature functions of decomposition pressures of the ternary compounds on the quasibinary line Bi₂O₃/BiI₃ were determined by total pressure measurements and mass spectrometry. The barogram of the system was constructed and the melting diagram precised. The enthalpies of formation and the standard entropies of the solid phases were derived from the decomposition functions: (Values see Inhaltsübersicht).     

Syntheses and Crystal Structures of the Thallium(I) Iodobismuthates(III) Tl7Bi3I16 and Tl3BiI6

Dark grey (dark red with transmitting light) crystals of heptathallium(I) hexadecaiodo‐tribismuthate(III), Tl₇Bi₃I₁₆, were obtained by slow cooling of a melt from 800 K to ambient temperature and, with higher crystal quality via solvothermal synthesis in aqueous HI by slowly cooling from 428 to 363 K. The compound is diamagnetic and melts congruently at 630(5) K. X‐ray diffraction on single‐crystals revealed that Tl₇Bi₃I₁₆ crystallizes in the orthorhombic space group Cmcm with lattice parameters a = 2473.4(5), b = 1441.9(2), c = 3616.9(7) pm. The crystal structure can be interpreted as a layered intergrowth of fragments from the CsNiCl₃ and K₅Dy₃I₁₂ structure types with isolated [BiI₆]^3? octahedra and [Bi₂I₁₀]^4? double octahedra. Rotation and distortion of the complex anions establish coordination numbers (c.n.) between 7 and 9 for the Tl⁺ cations. Dark red crystals of trithallium(I) hexaiodo‐bismuthate(III), Tl₃BiI₆, are only accessible via hydrothermal synthesis in aqueous HI and slowly cooling from 428 to 363 K. Thermal analysis reveals a peritectoid decomposition at 540(5) K into the neighboring phases Tl₇Bi₃I₁₆ and TlI. Tl₃BiI₆ crystallizes in the monoclinic space group P2₁/c with lattice parameters a = 1352.6(3), b = 899.6(2), c = 1353.8(3) pm, and β = 104.18(3)°. In the crystal structure isolated [BiI₆]^3? octahedra are arranged according to the motif of a face‐centered pseudo‐cubic packing. Due to the tilted orientation of the [BiI₆]^3? groups the Tl⁺ cations have c.n. of 8 and 9. Although the crystal structure of Tl₃BiI₆ looks like a distorted variant of the elpasolith type, there is no symmetry relation according to a group subgroup formalism.     

Preparation and crystal structure of [Bi3I(C4H8O3H2)2(C4H8O3H)5]2Bi8I30 containing the novel polynuclear [Bi8I30] anion

Preparation and crystal structure of the novel compound [Bi₃I(C₄H₈O₃H₂)₂(C₄H₈O₃H)₅]₂Bi₈I₃₀ are reported. The title compound is prepared by heating of BiI₃ and diethylene glycol at 413 K in a sealed quartz glass tube filled with argon. Deep red single crystals are grown and applied to perform X-ray powder diffraction and X-ray single-crystal diffraction measurements. The compound crystallizes triclinic with space group P-1: Z=2, a=13.217(1) Å, b=15.277(1) Å, c=22.498(1) Å, α=84.33(1), β=73.18(1), γ=67.48(1). [Bi₃I(C₄H₈O₃H₂)₂(C₄H₈O₃H)₅]₂Bi₈I₃₀ comprises the novel polynuclear [Bi₈I₃₀]⁶⁻ anion and [Bi₃I(C₄H₈O₃H₂)₂(C₄H₈O₃H)₅]³⁺ as the cation. Cation as well as the anion can be assumed to represent intermediates between solid BiI₃ and BiI₃ completely dissolved in diethylene glycol.     

Untersuchungen zum quasibinären System Bi2Se3/BiI3

Investigations on the Pseudobinary System Bi₂Se₃/BiI₃ The phase diagram of the pseudobinary system Bi₂Se₃/BiI₃ was investigated by DTA, total pressure measurements and x-ray phase analysis. Only BiSeI exist as a ternary phase in this system. The compound melts incongruently at 545 °C. Heat of formation and standard entropy were calculated from vapor pressure data.ΔH_B° (BiSeI, f, 298) = (–23.4 ± 1.9) kcal/mol S°(BiSeI, f, 298) = (38.7 ± 3.5) cal/K · mol     

Wismutmonojodid BiJ,eine Verbindung mit Bi(O) und Bi(II)

Bismuth Monoiodide, a Compound with Bi(O) and Bi(II) Bismuth monoiodide was synthesized in closed tubes from the elements as well as from Bi and HgI₂ as a black coloured crystalline compound. With increasing temperature BiI passes two transitions. α-BiI is stable below 370 K and changes to β-BiI by a martensitic transition. γ-BiI is the stable modification above 564 K and decomposes at 585 K peritectically to BiI₃ and a lower iodide. All three modification crystallize in the monoclinic space group C2/m. The structures (single crystal studies) of α-BiI and β-BiI are characterized by onedimensional infinite chains [Bi₄I₄] with covalent bonds but only weak interactions in between. The [Bi₄I₄]-chains are built up by two completely different Bi atoms. Bi(A) is only bonded to three Bi whereas Bi(B) has bonds to one Bi and four I. The average bond lengths are Bi? Bi = 304.5 pm and Bi? I = 313.7 pm respectively. The configuration of the Bi(A) atoms is typical for Bi^O and that one of the Bi(B) atoms is characteristic for Bi²⁺ with the electron configuration s²p¹. Therefore, α-BiI and β-BiI are mixed valence compounds [Bi^OBi²⁺I₄]. The structures are variants of the simple cubic polonium type of structure and differ in the stacking of connected units. The structures and their transitions, the possible configurations for monohalides BiX on principle as well as the energy balances of the disproportionation of Bi⁺ are discussed together in detail.     

Synthesis,second-harmonic generation (SHG), and photoluminescence (PL) properties of noncentrosymmetric bismuth selenite solid solutions,Bi2-xLnxSeO5 (Ln = La and Eu; x = 0–0.3)

A series of La³⁺ or Eu³⁺-doped noncentrosymmetric (NCS) bismuth selenite solid solutions, Bi_2-xLn_xSeO₅ (x = 0.1, 0.2, and 0.3), have been successfully synthesized via standard solid-state reactions under vacuum with Bi₂O₃, La₂O₃ (or Eu₂O₃), and SeO₂ as starting materials. Crystal structures and phase purities of the resultant materials were thoroughly characterized by powder X-ray diffraction using the Rietveld method. The results clearly show that the reported materials crystallize in the orthorhombic space group, Abm2 (No. 39), and exhibit pseudo-three-dimensional frameworks consisting of BiO₃, BiO₅, and SeO₃ polyhedra that share edges and corners. Detailed diffraction studies indicate that the cell volume of Bi_2-xLn_xSeO₅ decreases with an increasing amount of Ln³⁺ on the Bi³⁺ sites. However, no ordering between Ln³⁺ and Bi³⁺ was observed in the Bi_2-xLn_xSeO₅ solid solutions. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that SHG efficiencies of Bi_2-xLn_xSeO₅ solid solutions continuously decrease as more Ln³⁺ cations are added to the sites of polarizable Bi³⁺ cations. Photoluminescence (PL) measurements on Bi_2-xEu_xSeO₅ exhibit three specific emission peaks at 592, 613, and 702 nm (⁵D₀ → ⁷F_{1, 2, 4}) owing to the 4f-4f intrashell transitions of Eu³⁺ ions.     

Copper- and silver-containing heterometallic iodobismuthates(iii) with 4-(dimethylamino)-1-methylpyridinium cation: structures,thermal stability and optical properties

Reactions of BiI₃, copper or silver iodide and 4-(dimethyl-amino)-1-methylpyridinium iodide [(Me-DMAP)I] result in formation of heterometallic complexes (MeDMAP)₂{[Bi₂Cu₂I₁₀]} and (MeDMAP)₂{[Bi₂Ag₂I₁₀]}. Their crystal structures, thermal stability and optical properties have been studied. Optical band gaps calculated from diffuse reflectance spectroscopy data are 1.81 and 2.06 eV for copper- and silver-containing complexes, respectively.     

Zur thermischen Zersetzung von TeSeO4 und Te3SeO8 – Koexistenzbeziehungen im ternären System TeO2/SeO2/Bi2SeO5

Thermal Decomposition of TeSeO₄ and Te₃SeO₈ – Phase Relations in the Ternary System TeO₂/SeO₂/Bi₂SeO₅ The saturation decomposition pressure of TeSeO₄ and Te₃SeO₈ were determined in a membran zero manometer. From the equilibrium data are derived the Enthalpies of formation and the Standard Entropies: Data see Inhaltsübersicht. Thus the coexistence ranges in the ternary triangle TeO₂/SeO₂/Bi₂SeO₅ can be determined. Informations about the melting diagram obtained by thermal analysis of the condensed compositions TeO₂/SeO₂.     

Untersuchungen zur thermischen Zersetzung der Ammoniumyttriumhalogenide I. Ammoniumyttriumchloride

Investigation on the Thermal Decomposition of Ammonium Yttrium Halides. I. Ammonium Yttrium Chlorides (NH₄)₃YCl₆ decomposes in first step to the solid phase NH₄Y₂Cl_7,s and gaseous NH_3,g and HCl_g. NH₄Y₂Cl_7,s decomposes in a second step to YCl₃, NH₃ and HCl. The decomposition-pressure-functions are given and from this the enthalpies of formation and the standard entropies of the phases are derived.     

Gasphasengleichgewichte quaternärer Bismut‐Selen‐Oxidchloride

Gas‐Phase Equilibria of Quaternary Bismuth Selenium Oxidechlorides The existence of new compounds Bi₄O₄SeCl₂, Bi₁₀O₁₂SeCl₄, and Bi₂₂O₂₈SeCl₈ in the pseudoternary area Bi₂O₃/Bi₂Se₃/BiCl₃ has been established by solid state and chemical vapour transport reactions. Furthermore, heterogeneous equilibria between solid state and vapour phase have been studied by mass‐spectrometric measurements. The novel gas‐molecule BiSeCl has been detected. The results of ab initio calculations for structure and refining of thermochemistry of this molecule are given: (Bi–Se) = 2,44 Å; (Bi–Cl) = 2,49 Å; (Se–Bi–Cl) = 106,0°; Thermodynamics: δH°_B,298 (BiSeCl_g) = 6,0 kcal/mol; S°₂₉₈ (BiSeCl_g) = 75,8 cal/mol K; Cp (BiSeCl_g) = 13,583 + 0,64 · 10^–3 · T – 0,41 · 10⁵ · T^–2 – 0,35 · 10^–6 · T² cal/mol K. Finally, the composition of the gaseous phase has been calculated and estimations about chemical vapour transport were carried out by thermodynamic modelling.     

Exploration of New Birefringent Crystals in Bismuth d0 Transition Metal Selenites

The first examples of bismuth fluoride selenites with d⁰-TM/Te^VI polyhedrons, namely, Bi₄TiO₂F₄(SeO₃)₄ ( 1 ), Bi₄NbO₃F₃(SeO₃)₄ ( 2 ), Bi₄TeO₄F₂(TeO₃)₂(SeO₃)₂ ( 3 ), Bi₂F₂(MoO₄)(SeO₃) ( 4 ) and Bi₂ZrO₂F₂(SeO₃)₂ ( 5 ) have been successfully synthesized under hydrothermal reactions by aliovalent substitution. The five new compounds feature three different types of structures. Compounds 1 – 3 , containing Ti^IV, Nb^V and Te^VI respectively, are isostructural, exhibiting a new 3D framework composed of a 3D bismuth oxyfluoride architecture, with intersecting tunnels occupied by d⁰-TM/Te^VI octahedrons and selenite/tellurite groups. Interestingly, compound Bi₄TeO₄F₂(TeO₃)₂(SeO₃)₂ ( 3 ) is the first structure containing Se^IV and mixed-valent Te^IV/Te^VI cations simultaneously. Compound 4 features a new 3D structure formed by a 3D bismuth oxyfluoride network with MoO₄ tetrahedrons and selenites groups imbedded in the 1D tunnels. Compound 5 displays a novel pillar-layered 3D open framework, consisting of 2D bismuth oxide layers bridged by the [ZrO₂F₂(SeO₃)₂]⁶⁻ polyanions. Theoretical calculations revealed that the five compounds displayed very strong birefringence. The birefringence values of compounds 1 – 3 , especially, are above 0.19 at 1064 nm, which are larger than the mineral calcite. Based on the structure and property analysis, it was found that the asymmetric SeO₃ groups (and TeO₃ in compound 3 ) displayed the largest anisotropy, compared with the bismuth cations and the d⁰-TM/Te polyhedra, which is beneficial to the birefringence.     

Phase Equilibrium in the SeO2–Bi2O3 System

The subject of the present study is the system SeO₂-Bi₂O₃ that comprises two oxides with low melting points. All batches are thermal treatment in quartz ampoules, which are evacuated and sealed at a pressure P=0.1 Pa. On the basis of DTA (differential thermal analysis) and X-ray data, the most probable liquidus line of the system has been plotted. The eutectic composition lies about 90 mol% SeO₂,with on eutectic temperature at 230°C. Above 20 mol% Bi₂O₃ the liquidus temperature extremely increases. The formation of three compounds is proved:Bi₂Se₃O₉ and Bi₂Se₄O₁₁ are melting incongruently at 540 and 350°C respectively and Bi₂SeO₅ congruently at 915°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Syntheses and crystal structures of several novel alkylammonium iodobismuthate materials containing the 1,3-bis-(4-piperidinium)propane cation

The inorganic-organic salts (H₂TMDP)₃(Bi₂I₉)₂ (1), (H₂TMDP)₂(Bi₄I₁₆)·2EtOH (2), (H₂TMDP)₂(Bi₆I₂₂)·2EtOH (3), and (H₂TMDP)₂(Bi₆I₂₂) (4) were synthesized and structurally characterized from the solvothermal reaction of 1,3-bis-(4-piperidyl)propane (TMDP) and BiI₃ by adjusting the relative ratio of the reactants. The anions of the compounds consist of 2 (1), 4 (2), or 6 (3 and 4) BiI₆ polyhedra, which are joined by face- (1) or edge-sharing (2-4) to form discrete anions. The size of the discrete anion, in terms of the number of connected polyhedra, is observed to increase as the ratio of BiI₃ to TMDP is increased. A related compound (H₂TMDP)(Bi₃I₁₁)·(H₂O) (5) was synthesized and structurally characterized using the same two reactants in the presence of HF. The anion of 5 is polymeric rather than discrete, with a trioctahedral repeat unit.     

Synthese und Kristallstrukturen von (Ph4P)4[Bi8I28], (nBu4N)[Bi2I7] und (Et3PhN)2[Bi3I11] – Iodobismutate mit isolierten bzw. polymeren Anionen

Synthesis and Crystal Structures of (Ph₄P)₄[Bi₈I₂₈], (ⁿBu₄N)[Bi₂I₇], and (Et₃PhN)₂[Bi₃I₁₁] – Bismuth Iodo Complexes with Isolated and Polymeric Anions Solutions of BiI₃ in methanol react with NaI and (ⁿBu₄N)(PF₆) or (Et₃NPh)(PF₆) to form anionic bismuth iodo complexes (ⁿBu₄N)[Bi₂I₇] 1 and (Et₃PhN)₂[Bi₃I₁₁] 2 . In 1 Bi₄I₁₆ units, and in 2 Bi₆I₂₄ units are linked by common I-atoms to onedimensional infinite chains. Reaction of BiI₃ with (Ph₄P)(PF₆) in methanol yields (Ph₄P)₄[Bi₈I₂₈] 3 . The anions of 1–3 consist of edge-sharing BiI₆ octahedra. (ⁿBu₄N)[Bi₂I₇] 1 : Space group I2/m (No. 13), a = 1 082.3(5), b = 2 597.1(13), c = 1 206.1(6) pm, β = 93.17(2)°, V = 3 385(3) · 10⁶ pm³; (Et₃PhN)₂[Bi₃I₁₁] 2 : Space group P1 (No. 2), a = 1 283.5(6), b = 1 345.9(7), c = 1 546.3(8) pm, α = 83.87(2), β = 74.24(2), γ = 68.26(2)°, V = 2 388(2) · 10⁶ pm³; (Ph₄P)₄[Bi₈I₂₈] 3 : Space group P1 (No. 2), a = 1 329.3(4), b = 1 337.0(4), c = 2 193.1(5) pm, α = 104.20(2), β = 99.73(2), γ = 100.44(2)°, V = 3 622(2) · 10⁶ pm³.     

Three inorganic-organic hybrids of bismuth(III) iodide complexes containing substituted 1,2,4-triazole organic components with charaterizations of diffuse reflectance spectra

The reactions of two kinds of substituted 1,2,4-triazoles with BiI₃ yielded three inorganic-organic hybrids: [HL1]₄[Bi₆I₂₂]·[L1]₄·4H₂O (1) (L1=3-(1,2,4-triazole-4-yl)-1H-1,2,4-triazole); [HL2]₄[Bi₆I₂₂]·6H₂O (2); [HL2]₂[Bi₂I₈]·[L2]₂ (3) (L2=(m-phenol)-1,2,4-triazole). Both 1 and 2 have polynuclear anions of [Bi₆I₂₂]^4- to build up the inorganic layers and substituted 1,2,4-triazoles as the organic layers. Hybrid 3 consists of two BiI₅ square pyramids as inorganic layers. There exist hydrogen bondings and I?I interactions in the structures of 1, 2 and 3. Optical absorption spectra of 1, 2 and 3 reveal the presence of sharp optical gaps of 1.77, 1.77 and 2.07 eV, respectively, suggesting that these materials behave as semiconductors.     

Zum Chemischen Transport von Cr2O3 mit Cl2 und mit HgCl2 ? Experimente und Modellrechungen

On the Chemical Transport of Cr₂O₃ with Cl₂ and with HgCl₂ — Experiments and Model Calculations The migration of Cr₂O₃ in a temperature gradient (1 000°C → 900°C) in the presence of low concentrations of chlorine and water (from the wall of silica ampoules) is a result from the endothermic reactions (1) Cr₂O_3,s + H₂O_g + 3 Cl_2,g = 2 CrO₂Cl_2,g + 2 HCl_g (2) Cr₂O_3,s + 1/2 O_2,g + 2 Cl_2,g = 2 CrO₂Cl_2,g With higher concentrations of chlorine, the transport reaction is (3) Cr₂O_3,s + 5/2 Cl_2,g = 3/2 CrO₂Cl_2,g + 1/2 CrCl_4,g The gas phase of the transport system Cr₂O₃/Cl₂ can be reduced step by step by adding small amounts of chromium, so that CrCl₃ and finally also CrCl₂ become more important. Further, at a lower ratio n°(Cl)/n°(Cr) three transport reactions have to be taken into consideration; with the participation of CrOCl_2,g (5). (4) Cr₂O_3,s + 9/2 CrCl_4,g = 3/2 CrO₂Cl_2,g + 5 CrCl_3,g (5) Cr₂O_3,s + 3 CrCl_4,g = 3 CrOCl_2,g + 2 CrCl_3,g (6) Cr₂O_3,s + H_2,g + 4 HCl_g = 2 CrCl_2,g + 3 H₂O_g The reactions (1), (2) and (6) become possible through the cooperation of two transport agents at a time. The migration of Cr₂O₃ with HgCl₂ can also be described with reactions (1) – (3). The decomposition of HgCl₂ Produces the small chlorine pressure for the transport reaction. The oxidation potential of the transport agent HgCl₂ is too low for the oxidation of Cr^III to Cr^VI.     

A New Iodobismuthate-Based Hybrid Containing Mixed Iodobismuthate Clusters Templated by Diammonium Cation: Structure and Photocurrent Response

A new iodobismuthate-based hybrid (Me₂DABCO)₇(BiI₆)₂(Bi₂I₉)₂.2I₃ (1) (Me₂DABCO²⁺ = N,N′-dimethyl-1,4- diazabicyclo[2.2.2] octane) has been structurally determined. The highly interesting feature of 1 lies in its presence of mixed types of iodobismuthate clusters, i.e. mononuclear (BiI₆)^3? and (Bi₂I₉)^3? dimer in one crystal lattice templated by Me₂DABCO²⁺ cation, which is the first example of mixed iodobismuthate clusters in one lattice. Its absorption zone can be broadened compared with other single iodobismuthate cluster-containing analogy compounds. And due to the strong I···I interactions, an optical gap of 1.61 eV can be observed. The photocurrent response properties before and after heating were discussed, which suggests that the device can be potentially used as temperature-response switch.     

Reactions of bismuth iodide with ammonium,phosphonium, and bismuthonium salts

The reactions of ammonium, phosphonium, and bismuthonium salts with bismuth iodide were used to synthesize a series of complex compounds with bismuth-containing anions: [(HOC₂H₄)₃NH]⁺ ₄[Bi₄I₁₆]^4?, [Ph₃EtP] ₃ ⁺ [Bi₂I₉]^3?, and [Ph₄Bi] ₃ ⁺ [Bi₅I₁₈]^3?. X-ray diffraction data show that the nitrogen atoms in the two types of crystallographically independent cations of the nitrogen-containing complex possess a distorted tetrahedral coordination [the CNC angles are 110.3(9)°–113.2(9)°]. In the tetranuclear centrosymmetric [Bi₄I₁₆]^4? anion, the bismuth atoms have an octahedral coordination: Two types of groups, BiI₂ and BiI₃, are bound with one another by four μ₂-and two μ₃-iodine bridges (the Bi-I-μ₂, Bi-I-μ₃, and Bi-I-μ₁ distances are 3.1296(10), 3.2808(8); 3.3210(8) and 2.8670(8)–2.9108(9) Å, respectively). The coordination of the phosphorus atom in the [Ph₃EtP]⁺ cations of the phosphorus-containing complex is close to tetrahedral (the CPC angles are 107.5°–114.1°). In the binuclear [Bi₂I₉]^3? anions, the bismuth atoms have an octahedral coordination. The axial I-Bi-I angles are 167.52(2)°, 169.84(2)°, and 174.97(2)°. The terminal BiI₃ fragments [Bi²-I^7,8,9 2.9238(7), 2.9236(7), and 2.9522(7) Å] are in the eclipsed conformation.