Structure Of Sb Research Articles

Different complexation behavior of a proton transfer compound obtained from 1,10‐phenanthroline and pyridine‐2,6‐dicarboxylic acid with Sn(IV), Sb(III) and Tl(I)

AbstractThe different complexation methods of a proton transfer compound, (phenH)2(pydc) (phen=1,10‐phenanthroline; pydcH2= pyridine‐2,6‐dicarboxylic acid), are discussed and formation of [Sn(pydc)(phen)(OH)2]·3H2O (1), {[Sb(pydc)(phen)]2O}·2DMSO·4H2O(2) and [(Tl(pydcH)]n (3) complexes are reported. The characterization was performed using IR spectroscopy and X‐ray diffraction. The structures of Sn(IV) and Sb(III) complexes show that both cationic and anionic fragments of the starting proton transfer compound have been involved in the complexation. Whereas the structure of Tl(I) complex demonstrates that only the anionic fragment of (phenH)2(pydc) is contributed to the complexation. The complexes 1‐3 show a variety of structural features including mononuclear, binuclear and polymeric structures. In compounds (1), (2) and (3) a large number of hydrogen bonds are observed. These interactions play an important role in the formation and stabilization of supramolecular systems in the crystal lattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Passivation of InSb surface for manufacturing infrared devices

We studied the reduction of active surface states at the InSb/insulator interface by the reduction of hysteresis in C– V plots and by the performance of InSb diodes operated in photovoltaic mode. The InSb wafers were cleaned with CP4A etchant (HNO 3:CH 3COOH:HF:H 2O at 2:1:1:10). Then layers of 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 were deposited on the cleaned surfaced by plasma enhanced chemical vapor deposition (PECVD). After measuring the surface morphology by atomic force microscopy (AFM) the atomic percentage of each element in each compound (e.g. Si and O 2 in SiO 2 layer) was studied by energy-dispersive X-ray spectroscopy (EDX). By using photoemission spectroscopy (XPS), we showed that the SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers include Sb and/or SbO x and the Sb In antisite during deposition occurred and for this reason their etch rates differ from pure SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers. Then the gold metal was deposited on the samples and capacitance voltage measurement was made on the MIS samples. The results showed hysteresis free curves if the surface has been cleaned correctly. Finally by depositing the 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 on diode structure of InSb, the performance of diode in this case was compared with the anodic oxidation method. The results showed the performance of device is better than for the anodic oxidation method.

The electronic band structure of InN, InAs and InSb compounds

The electronic band structure of InN, InAs and InSb has been investigated by ETB. The ETB method has been formulated for sp3d2 basis and nearest neighbor interactions of the compounds and its energy parameters have been derived from the results of the present first principles calculations carried on InN, InAs and InSb. It has been found that the present ETB parameters can produce the band structure of the compounds successfully.

Different-dimensional structures of antimony formed selectively on graphite

When antimony (mostly Sb4) is deposited on highly oriented pyrolytic graphite (HOPG), in situ scanning tunneling microscopy images reveal that three-dimensional (3D) spherical islands, quasi-2D films and 1D nanowires (NWs) are formed. The spherical islands develop into faceted crystallites in the later growth stage. The lattice parameters of the 2D and 3D structures are close to those of α-Sb bulk, whereas the NWs appear in a compressed state. The Laplace pressure, which can reach the GPa range in a nanostructure, is considered the driving force for the compressive lattice structures of Sb NWs. We found conditions of controlling the dimensionality of Sb nanostructures in their self-assembly on HOPG to a certain extent. At room temperature and with a low Sb flux, 3D islands grow exclusively. At a substrate temperature of 100 °C, 2D and 1D structures are dominant when a high deposition flux is used, whereas only NWs are formed initially when a low flux is used. These results are explained in terms of different activation energies for Sb4 diffusion and conversion to a chemisorption or dissociation state on HOPG. As the temperature increases, the rate of conversion to the chemisorption or dissociation state increases more rapidly than that of diffusion since the chemisorption activation energy is much higher than the diffusion barrier of physisorbed Sb4, resulting in enhanced 2D and 1D structural nucleation and growth, which are further favored with the increase in deposition flux. The bonding nature of various Sb structures with a graphite surface and the conditions for growing aligned Sb NWs exclusively are discussed.

The structure of Sb(1 1 1) determined by photoelectron diffraction

The Sb(1 1 1) 4d 5/2 core level is found to contain three components. Using photoelectron diffraction, these are assigned to photoemission from the first layer, the second layer and the bulk, respectively. The binding energy for the first and second layer atoms is found to be 120 meV lower and 330 meV higher than for the bulk atoms, respectively. As a by-product of this assignment, the geometric structure of the surface is determined. No substantial relaxations are found.

Relativistic effects, infrared intensities, diffusion and lithiation in InSb

We consider In 4Sb 4H 18 cluster with zinc-blend structure of InSb. The cohesive energy and band gap of InSb were calculated by Unrestricted Hartree–Fock (UHF) and Density Functional Theory (DFT) method and it was shown that underestimated values of band gap can be decreased by considering the relativistic effects and in some cases InSb crystal even to be a semimetal. By calculating time-dependent DFT (TDDFT), the first three singlet and triplet excited energies were calculated and it was shown the 0.23 eV (band gap of InSb at 77 K) is placed between them. The infrared intensities were calculated and it is shown that the 367 cm −1 (294 cm −1 experimentally) mode can be attributed to the LO( Γ) in InSb. Finally it was shown that the Cadmium (Cd) diffuses substantially as Cd In and changes the first three singlet and triplet excited energies, but Lithium (Li) is placed in empty spaces of InSb crystal in the lithiation of InSb.

Unexpected product formed by the reaction of [2,6-(MeOCH 2) 2C 6H 3]Li with SbCl 3: Structure of Sb–O intramolecularly coordinated organoantimony cation

Reaction of [2,6-(MeOCH 2) 2C 6H 3]Li ( 1) with SbCl 3 in 1:1 molar ratio yielded except the intended product [2,6-(MeOCH 2) 2C 6H 3]SbCl 2 ( 2) unexpected complex 3 consisting of antimony anion [Sb 6Cl 22] 4− compensated by four intramolecularly coordinated organoantimony cations [2,6-(MeOCH 2) 2C 6H 3] 2Sb +. Compound 3 is labile in CH 2Cl 2(CHCl 3) solution and decomposes to compound 2 and SbCl 3. Both compounds were characterized by the help of 1H and 13C NMR spectroscopy, ESI-mass spectrometry and in the case of 3 by single crystal X-ray diffraction techniques.

Crystal Structure and Atomic Arrangement of δ-Phase Sb–Te Binary Alloy

The composition modulated Sb–Te binary thin films deposited by a RF sputtering method on SiO2/Si substrates annealed through a rapid thermal annealing process and conducted a high-resolution transmission electron microscopy (HR-TEM) study in order to investigate the atomic arrangement of the δ-phase Sb–Te binary alloys which contain Te from 16 to 37 at. %. Through the comparison with HR-TEM image and diffraction patterns viewed along <2110> and <1010> direction, we have revealed that the δ-phase Sb–Te alloy crystallized into P3m1 or R3m space group whether the number of layers is the multiple of three or not. We also expect from analogous Bi–Te system in earlier reports that as the Sb/Te ratio increases, total number of Sb layers in a unit cell increases. Therefore, based on above result, we suggested the atomic arrangement model composed of appropriate Sb2 and Sb2Te3 layer and obtained simulated images of <2110> zone axis.

Microscopic and Electronic Structure of Semimetallic Sb and Semiconducting AlSb Fabricated by Nanoscale Electrodeposition: An in Situ Scanning Probe Investigation

The nanoscale electrocrystallization of pure Sb and the compound semiconductor AlSb on Au(111) has been studied by in situ scanning probe techniques (STM and STS) employing an ionic liquid electrolyte, {AlCl3-[C4mim]+Cl-} (1:1) containing SbCl3. The characteristic changes of the electronic structures with varying potentials have been probed for the first time by normalized differential conductance spectra, (dI/dU)/(I/U). In the underpotential deposition range of Sb the formation of two layers is observed. For the first monolayer a (square root 3 x square root 3)R30 degrees structure is determined from atomically resolved STM images. During the deposition and dissolution of the Sb monolayers characteristic wormlike or spinodal structures appear indicating surface alloying of antimony with the gold substrate. Under overpotential conditions two different Sb structures have been observed. If the deposition potential is continuously stepped to -0.1 V, Sb nanostripes form. On the other hand, randomly dispersed small clusters occur if the potential is jumped from 0.0 to -0.3 V vs Al/Al(III). Both modifications exhibit typical semimetallic behavior as shown by the STS spectra. At -1.1 V the cyclic voltammogram shows a clear reduction wave that is assigned to AlSb compound formation. Deposits in this potential range are characterized by a homogeneous distribution of clusters with diameters of approximately 20 nm. Conductance spectra of these clusters exhibit the main features of the electronic structure of the bulk semiconductor AlSb, with a band gap of 2.0 +/- 0.2 eV. Electrodeposition experiments on both sides of the compound deposition potential show a strong doping effect that is manifest in the corresponding conductance spectra.

C 6H 21N 4][Sb 9S 14O]: Solvothermal synthesis, crystal structure and characterization of the first non-centrosymmetric open Sb–S–O framework containing the new [SbS 2O] building unit

[C 6H 21N 4][Sb 9S 14O] represents the first known oxo-thioantimonate with an organic ion acting as structure director. The compound crystallizes in the non-centrosymmetric space group Cmc2 1 with a = 29.679 ( 2 ) , b = 9.9798 ( 6 ) , c = 11.7155 ( 7 ) Å , V = 3470.1 ( 4 ) Å 3 , Z = 4 . The structure contains the hitherto unknown [SbS 2O] unit as a structural motif. The [SbS 3] trigonal pyramids and [SbS 2O] units are joined to form a 10-membered ring with large pores having a diameter of 7.7 Å×8.3 Å. The organic template molecule acts like a tetra-dentate ligand around the O atom of the [SbS 2O] group. Depending on the value chosen for the Sb–S bond lengths, the material contains a 1-, 2- or 3-dimensional anion. The optical band gap of 2.03 eV demonstrates that the material is an optical semi-conductor. Upon heating, the compound decomposes in two steps yielding finally a mixture of Sb and Sb 2S 3. The 121Sb Mössbauer spectrum shows a relative large line width in accordance with the superposition of the five signals.

Photocatalytic Properties and 121Sb Mössbauer Spectra of Antimonic Acid Fine Nanoparticles Prepared by Soft Chemical Solution Process

Two kinds of dispersed nanoparticle photocatalysts of antimonic acid, HSbO 3 ·nH 2 O, namely, SbI and SbII, were prepared separately by the direct reactions of an aqueous H 2 O 2 solution with Sb alkoxide complex, Sb(O-i-C 3 H 7 ) 3 and metallic Sb powder according to a soft chemical solution process. Their photocatalytic properties were evaluated from methylene blue (MB, C 16 H 18 N 3 SCl) degradation. SbI showed very strong adsorption capability and high photocatalytic activity under UV light irradiation. The average rates of MB degradation were estimated to be 2.403 x 10 -5 m mol h -1 for SbI and 4.01 x 10 -6 m mol h -1 for SbII. To investigate the reason for their difference in photocatalytic MB degradation, the two Sb-based photocatalysts were characterized by 121 Sb Mossbauer spectroscopy in connection with powder X-ray diffraction and photoabsorption property measurement. The lattice parameters, particle sizes, and relative surface areas were estimated to be 10.372(3) A, 35 nm, and 43.5 m 2 g -1 for SbI and 10.362(4) A, 70 nm, and 31.4 m 2 g -1 for SbII, respectively. Valuable information was obtained on valence state and coordination structure of Sb contained in them. These results revealed that SbI had the advantages of high dispersion, fine crystallinity, and large relative surface area as well as only containing the octahedrally coordinated Sb 5+ species with d 10 electronic configuration, resulting in having the high photocatalytic activity for MB degradation under UV light irradiation. A small amount of Sb 3+ species with d 8 electronic configuration should be considered to be the main reason the photocatalytic performance of SbII for MB degradation was definitely lower than that of SbI.

Surface morphology of crystalline antimony islands on graphite at room temperature

Antimony islands of different shapes and dimensions were grown on highly orientedpyrolytic graphite (HOPG) at room temperature in ultrahigh vacuum. Three-dimensional(3D) spherical, 2D thin films and 1D nanorods of Sb on graphite were studiedusing in situ scanning tunnelling microscopy. Sb was evaporated in the form ofSb4, which interacts with HOPG weakly and exhibits a high surface mobility, resulting inpreferential nucleation of 3D spherical islands at defect sites. Surface diffusion andaggregation lead to the formation of nanoparticles with various shapes and sizes. The shapeand size of islands depend on growth parameters, i.e. flux and deposition time. The 3D and2D structures of Sb on graphite have the same bulk crystalline rhombohedral(α-Sb) structure, but the 1D nanorods show a highly compressed structure different from theα-Sb lattice.

Fermi Surface and Anisotropic Spin-Orbit Coupling of Sb(111) Studied by Angle-Resolved Photoemission Spectroscopy

High-resolution angle-resolved photoemission spectroscopy has been performed on Sb(111) to elucidate the origin of anomalous electronic properties in group-V semimetal surfaces. The surface was found to be metallic despite the semimetallic character of bulk. We clearly observed two surface-derived Fermi surfaces which are likely spin split, demonstrating that the spin-orbit interaction plays a dominant role in characterizing the surface electronic states of group-V semimetals. The universality or dissimilarity of the electronic structure in Bi and Sb is discussed in relation to the granular superconductivity, electron-phonon coupling, and surface charge or spin density wave.

Structure of lintnerized starch is related to X-ray diffraction pattern and susceptibility to acid and enzyme hydrolysis of starch granules

Acid-resistant residues (lintnerized starches, Ls) were prepared from starches showing A-, B- and C- X-ray diffraction patterns. Ls retained the same X-ray crystalline type as their native counterparts with an improvement in diffraction intensity. Fluorophore-assisted capillary electrophoresis (FACE) study indicated that structural characteristics of Ls were associated with X-ray diffraction patterns. Double helices originated from linear chains with an approximate average degree of polymerisation (DP) 14, 16, and 15 would span the entire length of crystalline lamellae of A-, B-, and C-type starches, respectively. The proportion of singly branched materials (SB) with DP 25 protected in Ls was higher for A-type Ls (10–17%) than for B-type Ls (4–6%) and C-type Ls (8%). The structures of SB were similar in which branched chain (DP 13–15) was longer than main chain (DP 10–12). The structural characteristics of Ls are discussed in relation to acid and enzymatic degradations of starch granules.

Pressure and temperature dependence of the structure of liquid InSb

We investigate the structure of liquid InSb over a wide pressure range up to 20 GPa and a wide temperature range up to 1570 K by synchrotron x-ray diffraction. With increasing pressure along the melting curve, the local structure, which is anisotropic near the ambient pressure, becomes more isotropic. However, at pressures higher than about 10 GPa, the pressure-induced change becomes less prominent, and the local structure contracts almost uniformly. Structural parameters deviate significantly from those in simple liquid metals in this pressure region, revealing a stable liquid form with an anisotropic local structure. The analysis of $g(r)$ reveals that the liquid is possibly interpreted by the local structure of a single species, whose $g(r)$ is apparently expressed by a linear combination of $g(r)$ for $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Sn}$-like and bcc-like local structures in a one-to-one ratio. This local structure is completely different from those present in its crystalline counterpart. Pressure and temperature dependence of the local structure is discussed in the relation to Rapoport two species model [J. Chem. Phys. 46, 2891 (1967)].

Defect structure of Sb 2−xMn xTe 3 single crystals

Incorporation of the transition metal elements in the tetradymite structure of Sb 2Te 3 has a strong influence on electronic properties. Recent studies have indicated that Mn substitutes on the Sb sublattice increases the carrier concentration of holes. However, the doping efficiency of Mn appears rather low in comparison to what it should be based on the measurements of magnetization, structural analysis, and transport properties. In this paper we address this issue by making detailed studies of the Hall effect and electrical resistivity and we explain the results with the aid of a model that takes into account interactions of the Mn impurity with the native defects in antimony telluride. Specifically, we find that Mn atoms interact with antisite defects (antimony atoms located on the tellurium sublattice), a process that decreases the density of antisite centers and generates free electrons. These, in turn, recombine with holes and thus decrease their concentration and the apparent Mn doping efficiency.

Interfacial segregation of dopants in fully silicided metal-oxide-semiconductor gates

We have investigated the structure of Sb and Al implanted NiSi∕SiO2 interfaces. The addition of dopants has been previously found to alter operating thresholds of silicide-gated field effect transistors. We find that Sb is segregated to an interfacial site, and is in a metallic bonding configuration. In contrast, interfacial Al is in an oxidized state. The two additives would appear to alter the threshold voltages by distinctly different mechanisms.

Synthesis and Crystal Structure of (Sb2Te2)[AlCl4], a Compound Containing a Heteroatomic Polymeric Cation (Sb2Te2+)n.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Phase Equilibria in the Ag—Dy—Sb System at 400 °C.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and Crystal Structure of (Sb2Te2)[AlCl4], a Compound Containing a Heteroatomic Polymeric Cation (Sb2Te2+)n

AbstractThe reaction of tellurium, antimony, antimony trichloride, sodium chloride, and an excess of aluminium trichloride in a closed evacuated glass ampoule yields dark red crystals of (Sb2Te2)[AlCl4]. During the reaction a melt is formed from which needle shaped crystals of the title compound grow on sublimating off the volatile AlCl3 at 130 °C. Energy dispersive X‐ray emission analysis showed the 1:1 ratio of Sb:Te. The crystal structure analysis (triclinic, P1¯, a = 949.30(2), b = 1348.24(3), c = 1804.97(5) pm, α = 78.983(2), β = 88.060(1), γ = 88.444(1)°, V = 2239.65(9)·106 pm3, Z = 8) shows that the structure is built of almost regular tetrahedral [AlCl4]‐ anions and of one‐dimensional polymeric (Sb2Te2+)ncations. The assignment of Sb and Te atoms to the respective atom positions of the cations was performed by an analysis of the occupation factors, a reasonable electron and charge distribution, and by the analysis of the cation‐anion interactions. The unit cell contains two symmetrically independent but almost isostructural cations which form strands made up of four‐membered stacked Sb2Te2 rings. These rings are connected with their neighboured rings alternatingly via two, three, and four covalent bonds. Predominantly Sb‐Te bonds are present, in smaller degree Sb‐Sb bonds, while Te‐Te bonds are not observed. The cationic strands can be interpreted by the Zintl concept in the connectivity of the different atom types and the resulting charges.