New transparent conductors with the M7O12 ordered oxygen-deficient fluorite structure: from In4Sn3O12 to In5.5Sb1.5O12

A new transparent conductor, containing pentavalent antimony, In_4+xSn_3−2xSb_xO₁₂, has been synthesized for 0?x?1.5. The latter exhibits an ordered oxygen-deficient fluorite structure with an ordered distribution of Sb⁵⁺ and In³⁺/Sn⁴⁺ species in the octahedral and seven-fold coordinated sites, respectively. More importantly, it is shown that the electronic conductivity of this transparent conducting oxide (TCO) at room temperature, is one order of magnitude larger for x=1 (In₅SnSbO₁₂) than for x=0 (In₄Sn₃O₁₂) and it turns to a semi-metallic behavior in contrast to In₄Sn₃O₁₂ which is a semi-conductor. The potential of this new material, as TCO, is also shown by its reflectance spectra, similar to In₄Sn₃O₁₂, involving only a small increase of the optical bandgap, by 0.15 eV.     

Electronic structure and low temperature thermoelectric properties of In₂₄M₈O₄₈ (M = Ge(4+), Sn(4+), Ti(4+), and Zr(4+))

The electronic structure and transport properties of In₂₄M₈O₄₈ (M = Ge⁴⁺, Sn⁴⁺, Ti⁴⁺, and Zr⁴⁺) have been studied by using the full‐potential linearized augmented plane‐wave method and the semiclassical Boltzmann theory, respectively. It is found that the magnitude of powerfactor with respect to relation time follows the order of In₂₄Sn₈O₄₈ > In₂₄Zr₈O₄₈ > In₂₄Ge₈O₄₈ > In₂₄Ti₈O₄₈. The largest powerfactor is 2.7 × 10¹² W/K²ms for In₂₄Sn₈O₄₈ at 60 K, which is nearly thirty times larger than those of conventional n‐type thermoelectric materials. The origin of the different thermoelectric behavior for these compounds is discussed from the electronic structure level. It is found that, at low temperature, the dopant strongly affect the bands near the Fermi level, which consequently leads to their different thermoelectric properties. The electronic configuration and the difference in atomic number between the dopant and the host atom also play an important role on the thermoelectric properties of In₂₄M₈O₄₈. Our calculations give a valuable insight on how to enhance the thermoelectric performance of In₃₂O₄₈. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

Notiz zur Kenntnis der roten Monohalogenide des Indiums,InX (X = CI,Br, I)

Inhaltsübersicht. Synthese (aus den Elementen; Einkristalle durch Sublimation im Gradienten: 200 → 100°C) und Strukturverfeinerung von InI (orthorhombisch, Cmcm, Z = 4; a = 476,3(1); b = 1278,1(1); c = 490,9(1) pm) werden beschrieben. Ein Vergleich mit InBr und InCl (alle TlI-Typ) weist auf die Bedeutung des 5s²-Elektronenpaares von In⁺ für diesen Strukturtyp und auf attraktive Wechselwirkungen in Richtung auf die Ausbildung eines Dimeren, In₂²⁺, hin. Note on the Red Monohalides of Indium, InX (X = CI, Br, I) Synthesis (from the elements; single crystals by sublimation in a 200 → 100°C gradient) and structure refinement of InI (orthorhombic, Cmcm, Z = 4, a = 476.3(1), b = 1278.1(1), c = 490.9(1) pm) are reported. A comparison with the isotypic halides InBr and InCl (all TlI type) hints at the importance of the 5s² electron pair of In⁺ for this structure type. Attractive interactions in the direction of the formation of a dimer, In₂²⁺, could play a role.     

Sulfonic cation exchangers based on immobilized cis-Calix[4]resorcinolarenes

New sulfonic cation exchangers based on immobilized calix[4]resorcinolarenes were prepared. Their ion-exchange properties toward Na⁺, Cu²⁺, [Pd(NH₃)₄]²⁺, In³⁺, and Sn⁴⁺ ions were studied in a wide pH range, and their chemical stability was examined.     

Macrocyclic Inorganic Tin-Containing Oxo Clusters: Heterometallic Strategy for Configuration and Catalytic Activity Modulation

In this work, the first examples of inorganic macrocyclic tin-oxo clusters which are stabilized by sulfate ligands are reported. As determined by X-ray diffraction and photoelectron spectroscopy analyses, the prepared inorganic Sn₁₀-oxo cluster displays interesting mixed valence behaviors, with 8 Sn⁴⁺ located at the cyclic skeleton and two Sn²⁺ encapsulated in the center. When further introducing Ti⁴⁺ and In³⁺ ions to the synthetic systems, heterometallic Sn₂Ti₆ and SnIn₅Ti₆ complexes with Ti₆(SO₄)₉ and SnIn₅(SO₄)₁₂ macrocyclic skeletons were prepared whose configuration and packing models were affected by the ionic radius of incorporated metals. Moreover, comparative CO₂ reduction experiments confirm that such heterometallic composition can significantly improve the catalytic activities of these inorganic macrocyclic oxo clusters. This work represents a milestone in constructing inorganic tin complexes and also macrocyclic metal oxo clusters with tunable configurations and properties.     

Zur Kenntnis des quasi-binären Systems InCl?SnCl2 und eine Anmerkung zum System KCl?SnCl2

On the Quasi-binary System InCl? SnCl₂ and a Remark on the System KCl? SnCl₂ We report the phase diagrams of the quasi-binary systems InCl/SnCl₂ and KCl/SnCl₂ derived from DTA and X-ray investigations. In both systems we find a nonstoichiometric phase having the formula A_2?2xSn_5+xC₁₂ (with 0 ? x ? 0.15 for A = In and 0 ? x ? 0.14 for A ? K), a peritectic ASn₂Cl₅ compound and a dystectic 1:1 phase. The nonstoichiometric phases are both isotypic with Th₇S₁₂. KSn₂Cl₅ crystallizes with a tetragonal NH₄Pb₂Br₅-type structure (sp. gr. 14/mcm; a = 803.55(3), c = 1387.5(5) pm) and InSn₂Cl₅ with a monoclinic NH₄Pb₂Cl₅-type arrangement (sp. gr. P2₁/c; a = 891.7(3), b = 800.2(3), c = 1251.0(4) pm, β = 89.55(5)°). The lattice constants for InSnCl₃ (a = 1680(3), b = 799.2(9), c = 845.4(10) pm, β = 90.8(1)°) were derived by indexing the X-ray powder diagram. In addition the InCl? SnCl₂ system contains a peritectic In₄SnCl₆ phase (sp. gr. Pmma; a = 1270(2), b = 2515(3), c = 1456 (1) pm, (single crystal data)) and a dystectic In₉SnCl₁₁ compound (tetragonal primitive; a = 864.6(2), c = 1219.3(6) pm (derived from indexed powder data)).     

Determination of excited state symmetry and g-value from the magnetic field dependence of the radiative decay time: KI: In+ and KI: Sn2+

An expression for the decay time as a function of an applied magnetic field is derived for the particular cases of A-band emission in KI: In⁺ and KI: Sn²⁺. Application of this analysis to the measured field dependence gives the value of g_⊥ for the emitting level as well as the symmetry of the relaxed excited state.     

Selecting indium-containing systems as solid electrolytes

Quasi-binary salt systems InCl₃-MeCl₂, where Me²⁺ stands for Mg²⁺, Cd²⁺, Zn²⁺, Sn²⁺, Co²⁺, or Mn²⁺, in the region of solid solutions on the basis of InCl₃ are considered. A comparative characteristic of some transport properties of these systems is given and optimum compositions for all systems under consideration are determined. The conduction mechanism that presumably takes place in systems InCl₃-MgCl₂ and InCl₃-CdCl₂ is confirmed by data that are obtained with the aid of the Tubandt method. In order to raise the reversibility with respect to the indium ion, also considered is the In₂S₃-InCl₃ system, in which the basis compound is In₂S₃. Methods of electroconduction and XRD are used to establish the existence of a region of limited solid solutions on the basis of indium sulfide. The current efficiency in a system with solid electrolyte In₂S₃-InCl₃ is determined (CE > 50%) and the dependence of the current efficiency on the electrolysis regime is considered. Thermodynamic investigation of some indium-containing compounds and the doping with indium are conducted with use made of indium-containing solid electrolytes of optimum compositions. Data concerning the magnitude of the alteration occurring in the Gibbs energy during the formation of indium-containing semiconducting compounds, which are close to reference data, are obtained.     

不同浓度Sn4+离子掺杂TiO2的结构、性质和光催化活性

采用溶胶-凝胶法制备出纯TiO₂和不同浓度Sn⁴⁺离子掺杂的TiO₂光催化剂(TiO₂-Snx%, x%代表Sn⁴⁺离子掺杂的TiO₂样品中Sn⁴⁺离子摩尔分数). 利用X 射线衍射(XRD)、X 射线光电子能谱(XPS)和表面光电压谱(SPS)确定了TiO₂-Snx%催化剂的晶相结构和能带结构, 结果表明: 当Sn⁴⁺离子浓度较低时, Sn⁴⁺离子进入TiO₂晶格, 取代并占据Ti⁴⁺离子的位置, 形成取代式掺杂结构(Ti_1-xSn_xO₂), 其掺杂能级在导带下0.38 eV处; 当Sn⁴⁺离子浓度较高时, 掺入的Sn⁴⁺离子在TiO₂表面生成金红石SnO₂, 形成TiO₂和SnO₂复合结构(TiO₂/SnO₂), SnO₂的导带位于TiO₂导带下0.33 eV处. 利用瞬态光电压谱和荧光光谱研究了TiO₂-Snx%催化剂光生载流子的分离和复合的动力学过程, 结果表明, Sn⁴⁺离子掺杂能级和表面SnO₂能带存在促进光生载流子的分离, 有效地抑制了光生电子与空穴的复合; 然而, Sn⁴⁺离子掺杂能级能更有效地增加光生电子的分离寿命, 提高了光生载流子的分离效率, 从而揭示了TiO₂-Snx%催化剂的光催化机理.     

A Review on Cs-Based Pb-Free Double Halide Perovskites: From Theoretical and Experimental Studies to Doping and Applications

Despite the progressive enhancement in the flexibility of Pb-based perovskites for optoelectronic applications, regrettably, they are facing two main challenges; (1) instability, which originates from using organic components in the perovskite structure, and (2) toxicity due to Pb. Therefore, new, stable non-toxic perovskite materials are demanded to overcome these drawbacks. The research community has been working on a wide variety of Pb-free perovskites with different molecular formulas and dimensionality. A variety of Pb-free halide double perovskites have been widely explored by different research groups in search for stable, non-toxic double perovskite material. Especially, Cs-based Pb-free halide double perovskite has been in focus recently. Herein, we present a review of theoretical and experimental research on Cs-based Pb-free double halide perovskites of structural formulas Cs₂M⁺M³⁺X6 (M⁺ = Ag⁺, Na⁺, In⁺ etc.; M³⁺= Bi³⁺, In³⁺, Sb³⁺; X = Cl⁻, Br⁻, I¯) and Cs₂M⁴⁺X₆ (M⁴⁺ = Ti⁴⁺, Sn⁴⁺, Au⁴⁺ etc.). We also present the challenges faced by these perovskite compounds and their current applications especially in photovoltaics alongside the effect of metal dopants on their performance.     

Maßanalyse und Katalyse

The direct titration of EDTA and DCTA as well as the determination of a number of metal ions (Zn²⁺, Cd²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Pb²⁺, Hg²⁺, Sn²⁺, Al³⁺, In³⁺, Ga³⁺, Th⁴⁺) by backtitration with manganese(II) standard solution is described. The decomposition of hydrogen peroxide and the reaction between hydrogen peroxide and resorcinol, both catalysed by manganese, have been used as indicator systems.     

Carbon-supported binary Li-Sn catalyst for acetylene hydrochlorination

The study of a novel catalyst containing LiCl and SnCl₂ (LiSn/AC) for acetylene hydrochlorination has been reported in this paper. Furthermore, the performance of both high activity (98.3%) and selectivity (>98.0%) are achieved by LiSn/AC catalysts under the reaction temperature of 200 °C and C₂H₂ hourly space velocity of 30 h^?1. The structural characteristics of the Sn based catalysts were deeply researched via BET, XRD, TEM, TPR, C₂H₂-TPD, XPS and TG techniques. According to these characteristic results, we proposed that the presence of Sn²⁺ exhibited better activity and stability than that of Sn⁴⁺ in Sn based catalysts. Additionally, LiCl additives not only can restrain the oxidation of Sn²⁺ and the loss of Sn⁴⁺ in fresh Sn based catalysts but also make the Sn^δ+ (δ = 2,4) species dispersed well on the surface of support. Therefore, the adsorption capacity of C₂H₂ and HCl was enhanced in LiSn/AC, which exhibited the better catalytic performance than that of Sn based catalyst.     

Zur Kenntnis der Phasen A2−2xSn5+xCl12 (A = K,In)

On the A_2?2xSn_5+xCl₁₂ (A = K, In) Phases The refinement of the structure of A_2-2xSn_5+xCl₁₂ compounds (A = K⁺, In⁺) with single crystal data is reported. They crystallize with the Th₇S₁₂ type arrangement (a = 1192(2) pm, c = 428.9(8) pm (K-compound); a = 1189.8(6) pm, c = 431.2(3) pm (In-compound)) for which we propose the space group P6 . The possibility of meroedric twinning is discussed. Due to the composition of these compounds the structure is necessarily disordered and this leads to a wide range of homogeneity which can be influenced by the size and the polarity of the A type cation.     

Luminescence properties of Eu2+, Sn2+, and Pb2+ in SrB6O10 and Sr1 − xMnxB6O10

The luminescence properties of Eu²⁺, Sn²⁺, and Pb²⁺ in SrB₆O₁₀ have been studied both at room-temperature and liquid-helium temperature and the decay times of Sn²⁺ and Pb²⁺ in this matrix have been measured and analyzed. According to the emission spectrum of Eu²⁺ there seems to be three different cation sites in SrB₆O₁₀. Europium, tin, and lead were also used as sensitizers for Mn²⁺ and the energy transfer processes were characterized. Eu²⁺-Mn²⁺ energy transfer was inefficient due to the transfer within different Eu²⁺ centers. The sensitization action of Sn²⁺ and Pb²⁺ on Mn²⁺ was different because lead-lead energy transfer occurs (even at 4.2 K) but tin-tin transfer can be neglected. A fast diffusion model for the Pb²⁺ system is suggested.     

Cation ordering in the fluorite-like transparent conductors In4+xSn3−2xSbxO12 and In6TeO12

The cation ordering in the fluorite-like transparent conductors In_4+xSn_3−2xSb_xO₁₂ and In₆TeO₁₂, was investigated by Time of Flight Neutron Powder Diffraction and X-ray Powder Diffraction (tellurate). The structural results including atomic positions, cation distributions, metal-oxygen distances and metal-oxygen-metal angles point to a progressive cation ordering on both sites of the Tb₇O₁₂-type structure with a strong preference of the smaller 4d¹⁰ cations (Sn⁴⁺, Sb⁵⁺, Te⁶⁺) for the octahedral sites. The corresponding increase of the overall structure-bonding anisotropy is analyzed in terms of the crystal chemical properties of the OM₄ tetrahedral network of the antistructure. The relationships between the M₇O₁₂ and the M₂O₃ bixbyite-type structures are explored. Within the whole series of compositions In_4+xM_3−xO₁₂ (M=Sn, Sb, Te) there exists an increase of the symmetry gap between the more symmetrical bixbyite structure and the M₇O₁₂ type. This is tentatively correlated with the progressive weakening of thermal stability of these compositions from Sn to Te via Sb.     

Mössbauer diagnosis of the electronic structure and local environment of <Superscript>119</Superscript>Sn in MgTiO<Subscript>3</Subscript>

Annealing of a hydroxide precursor containing equimolar amounts of Mg²⁺ and Ti⁴⁺ and small additions of Sn⁴⁺ (0.1 at %) in air at 900°C leads to titanate MgTiO₃ with an ilmenite structure. The ¹¹⁹Sn Mössbauer spectrum of the sample (unresolved doublet with the isomer shift δ = 0.10 ± 0.01 mm/s and the quadrupole splitting Δ = 0.49 ± 0.02 mm/s) is evidence that the tin atoms are still in the oxidation state +4. Annealing of the precursor at the same temperature in a hydrogen atmosphere yields MgTiO₃ containing Sn²⁺ ions (a doublet at δ = 2.82 ± 0.01 mm/s and Δ = 1.66 ± 0.03 mm/s) (the Sn²⁺/MgTiO₃ sample). According to the spectral parameters, the ¹¹⁹Sn²⁺ ions have a low coordination number (CN ? 6) and are abnormally resistant to reduction to the metal. Analogous features of the crystal-chemical behavior of ¹¹⁹Sn²⁺ were previously observed during the Mössbauer study of the samples containing tin on the surface of Cr₂O₃, α-Al₂O₃, and MgO crystallites. The conclusion drawn from analysis of the ¹¹⁹Sn²⁺ Mössbauer parameters that tin in the Sn²⁺/MgTiO₃ sample has surface localization was supported by X-ray photoelectron spectroscopy. Mössbauer measurements show that the tin of Sn²⁺/MgTiO₃ when in contact with air is oxidized much more slowly than on the surface of Cr₂O₃, α-Al₂O₃, or MgO crystallites. The inhibition of the oxidation reaction is explained to be due to passivation of adsorbed O₂ molecules caused by their interaction with mobile t _2g electrons of Ti³⁺ forming in titanate during high-temperature annealing in H₂. In addition to the Sn²⁺ doublet, the ¹¹⁹Sn spectrum shows a spectral component with parameters (δ ～ 1.6 mm/s, Δ ≤ 0.2 mm/s) not fitting the known tin species that can form in MgTiO₃. This component is explained by persistence in titanate of some Sn⁴⁺ ions immobilizing the mobile t _2g electron at one of their neighboring Ti⁴⁺ cations.     

Half Antiperovskites VI: On the Substitution Effects in Shandites InxSn2–xCo3S2

In the shandite type solid solution In_xSn_2–xCo₃S₂ the transition from half metal ferromagnetic Sn₂Co₃S₂ to the new thermoelectric InSnCo₃S₂ is related to A = In, Sn on different crystallographic sites. Effects and origin of crystal and electronic structure changes induced by A = In are now investigated within the solid solution 0 ≤ x ≤ 2 including In₂Co₃S₂. Effects are studied from X‐ray data, ¹¹⁹Sn Mößbauer spectroscopy, and ab initio calculations. Their origin is explored by DFT modeling on site preference of In and Sn in a supercell, electric field gradients (EFG), spin polarization, band structures, and direct space analyses (ELF, AIM). Indium is found to cause the crystal structure distortion on one A site, the electronic structure distortion to the other, as a consequence of inverted anisotropic bonding.     

Die neuen gemischtvalenten Chalkogenoindate MIn7X9 (M = Rb,Cs; X = S,Se): Strukturchemie,Röntgenund HRTEM‐Untersuchungen

The New Mixed Valent Chalcogenoindates MIn₇X₉ (M = Rb, Cs; X = S, Se): Structural Chemistry, X‐Ray and HRTEM Investigations Systematic X‐ray and HRTEM investigations on the ternary systems alkali metal (or thallium)–indium–chalcogen proved the existence of mixed valent solids with the simultaneous occurrence of indium species in different states of oxidation. Additionally to the earlier described solids MIn₅S₇ (M: Na, K, Tl: isotypic to InIn₅S₇ = In₆S₇ and TlIn₅S₇) and KIn₅S₆ (isotyp to TlIn₅S₆) in the actual work we present with MIn₇X₉ (M: Rb, Cs; X: S, Se) a new structure type which also contains indium in the states of oxidation +3 and +2. The formal state of oxidation In²⁺ corresponds to (In₂)⁴⁺ ions. A reasonable ionic formulation of these structures is given by: MIn₅S₇ = M⁺ 3[In³⁺] [(In₂)⁴⁺] 7[S^2–] (M = Na, K, Tl), MIn₅S₆ = M⁺ [In³⁺] 2[(In₂)⁴⁺] 6[S^2–] (M = K, Tl), MIn₇X₉ = M⁺ 3[In³⁺] 2[(In₂)⁴⁺] 9[S^2–]. The three structure types show common two dimensional structure elements which contain ethane analogous In₂X₆ units and cis and trans edge sharing double octahedron chains. The main interest of this work is a crystalchemical discussion taking into account the new compounds MIn₇X₉ and the results of special HRTEM investigations on MIn₇X₉. The HRTEM investigations aim on the identification and subsequent preparation of new phases which initially might be visible as nano size crystals or inclusions in the HRTEM only.     

Studies on the effects of doping cesium metal(III) halides of the type Cs3MIII2X9 (MIII = Sb or Bi, X = Cl or Br)

A series of compounds, Cs₃M^III₂X₉ (M^III = Sb and Bi, X = Cl or Br) are doped with impurity ions (Ba²⁺, Ca²⁺, Sn²⁺, Pb²⁺, Mg²⁺, Fe²⁺, Tl³⁺, In³⁺, Se⁴⁺). Lattices doped with Sn(II), Pb(II) and Se(IV) are colored. Sn-119m Mössbauer data are consistent with the donation of Sn-5s electron density from tin(II) to a conduction band to give a pseudo-tin(IV) electronic environment.     

Local structure and hyperfine interactions of Fe and Sn atoms in brownmillerite-like ferrite Sr2Fe1.98Sn0.02O5+x

Mössbauer spectroscopy has been applied for studying local environment of ⁵⁷Fe and ¹¹⁹Sn probe atoms within tin-doped Sr₂Fe_1.98Sn_0.02O_5+x (x?0.02) ferrite with the brownmillerite-type structure. ⁵⁷Fe Mössbauer spectra indicate no appreciable local distortions induced by the tin dopant atoms. The ¹¹⁹Sn spectra recorded below the magnetic ordering temperature (T_N) can be described as a superposition of two Zeeman sextets, which indicate that Sn⁴⁺ dopant ions are located in two non-equivalent crystallographic and magnetic sites. The observed hyperfine parameters were discussed supposing Sn⁴⁺ cations to replace iron cations in the octahedral (Sn_O) and tetrahedral (Sn_T) sublattices. It has been supposed that Sn⁴⁺ cations being stabilized in the tetrahedral sublattice complete their nearest anion surrounding up to the octahedral oxygen coordination “Sn_T⁴⁺”. Annealing of the Sr₂Fe_1.98Sn_0.02O_5+x in helium flux conditions at 950°C leads to formation of divalent Sn²⁺ cations with a simultaneous decrease of the contribution for the Sn_T⁴⁺ sub-spectrum. The parameters of combined electric and magnetic hyperfine interactions of the ¹¹⁹Sn²⁺ sub-spectrum underline that impurity atoms are stabilized in the sp³d-hybrid state in the oxygen distorted tetragonal pyramid. The analysis of the ¹¹⁹Sn spectra indicates a chemical reversibility of the processes Sn_T²⁺?Sn_T⁴⁺ within the tetrahedral sublattice of the brownmillerite-type ferrite.