Sb Atoms Research Articles

Synthesis and Structure of µ2-Oxo-Bis [(Pentafluoropropionato)-Tris(5-Bromo-2-Methoxyphenyl)Antimony

The synthesis of μ 2 -oxo- bis [(pentafluoropropionato) tris (5-bromo-2-methoxy­phenyl)­antimony] ( 1 ) has been curried out by the oxidative addition reaction of tris (5-bromo-2-methoxyphenyl)antimony with pentafluoropropionic acid in the presence of hydrogen peroxide at an equimolar ratio of reactants. The compound is characterized by IR spectroscopy and X-ray diffraction analysis. According to X-ray diffraction data, there are two types of crystallographically independent molecules with slightly different geometrical parameters in the crystal. The antimony atoms in each molecule are linked by the bridging oxygen atom (the SbOSb angle is 167.6(7)°). The trigonal bipyramidal coordination of antimony atoms is distorted; the axial OSbO angles are 175.9(4)°, 174.5(4)° for Sb(1) and Sb(2) atoms, respectively. The sums of valence CSbC angles in the equatorial planes are 359.6(6)° and 356.4(6)°. The mean values of the Sb(1)–C and Sb(2)–C bond lengths are 2.12(2) Å, the Sb–O( μ 2 ) distances are 1.89(1), 1.98(1) Å. The carboxylate ligands in each molecule are monodentate. The distances between the antimony atoms and the corresponding terminal oxygen atoms are 2.22(1), 2.39(1) Å, the Sb···O=C distances are 3.38(2), 3.71(1) Å. The d(Sb···O=C)/d(Sb–О) ratios, which can be used to estimate the asymmetry of the ligand related to metal atom coordination, are 1.67 and 1.41. In crystal 1 there are such contacts as Sb···OMe (2.88(1)–3.16(1), 3.01(1)–3.20(1) Å), hydrogen bonds involving halogen atoms H···F (2.16, 2.50, 2.58 Å), H···Br (2.92, 2.96, 3.04 Å) and carbonyl oxygen atoms H···О (2.43, 2.59 Å), as well as halogen···halogen F···F interactions (2.70, 2.71 Å).

Antimony(i) → Pd(ii) complexes with the (μ-Sb)Pd2 coordination framework.

The reaction of the antimony(i) compound ArSb (1) (where Ar = C6H3-2,6-(CH[double bond, length as m-dash]NtBu)2) with various dimeric allyl palladium(ii) complexes [Pd(η3-allyl)(μ-X)]2 (where allyl = C3H5 or C3H4Me; X = Cl or CF3CO2) in a 1 : 1 stoichiometric ratio gave unique complexes with the μ-ArSb moiety bridging two palladium fragments, i.e. [{Pd(η3-C3H5)Cl}2(μ-ArSb)] (2), [{Pd(η3-C3H4Me)Cl}2(μ-ArSb)] (3) and [{Pd(η3-C3H5)(CF3CO2)}2(μ-ArSb)] (4). Compound 1 serves formally as a 4e donor in 2-4. The treatment of 2 with another equivalent of ArSb led to the formation of the [Pd(η3-C3H5)(Cl)(μ-ArSb)] complex (5), proving that 1 is able to function as a 2e donor in target complexes as well. The structures of 2-5 were described in detail both in solution (NMR and mass spectrometry) and in the solid state (single crystal X-ray diffraction analysis). DFT methods were used to compare bonding in the 1 : 1 (5) and 1 : 2 (2) complexes. Furthermore, a comprehensive 121Sb Mössbauer spectroscopic investigation of complexes 2 and 5 along with parent ArSbCl2 (6) and 1 was performed. For comparison, complexes [Fe(CO)4(ArSb)] (7) and [Mo(CO)5(ArSb)] (8) were also included in this study.

Syntheses and Structures of the Hexacoordinated Antimony Complexes: Ph3(C2H4O2)Sb⋅⋅⋅DMSO, (3-FC6H4)3(C2H4O2)Sb⋅⋅⋅DMSO, and (4-MeC6H4)3(C6H4O2)Sb⋅⋅⋅DMSO

Complexes Ph3(C2H4O2)Sb⋅⋅⋅DMSO (I), (3-FC6H4)3(C2H4O2)Sb⋅⋅⋅DMSO (II), and (4‑MeC6H4)3-(C6H4O2)Sb⋅⋅⋅DMSO (III) are synthesized by the reactions of triarylantimony with ethylene glycol or pyrocatechol in the presence of an oxidant and dimethyl sulfoxide (DMSO). According to the X-ray diffraction analysis data, the Sb atoms in the complexes have the coordination of a distorted octahedron with the chelate cycle (C2H4O2 or C6H4O2) and two aryl groups in the equatorial plane, and the third aryl group and DMSO molecule occupy the axial positions. The СSbO axial angles are 173.59(5)° (I); 175.96(8)°, 175.93(8)° (II); and 174.07(8)° (III). The Sb⋅⋅⋅О=SMe2 distances (2.346(2)−2.407(2) A) considerably exceed the sum of covalent radii of the atoms.

Bismuth and antimony chalcogenides: Peculiarities of electron density distribution, unusual magnetic properties and superconductivity

Abstract Electron band structure calculations and analysis of critical points parameters in the electron density distribution in Bi2Te3, Bi2Se3, Bi2S3, α-Bi2O3, Sb2Te3, Sb2Se3 and Sb2S3 at ambient and high pressures were performed to determine interrelations between the crystal structure, unusual physical (including magnetic and superconducting) properties and peculiarities in the electron density distribution. The programming code WIEN2k was used for band structure calculations. The previously found correlation between the superconducting transition temperature Tc and the electron density Laplacian value in the bond critical point with the highest electron density was confirmed by the calculations made for crystal structures under high pressure. The revealed parameters of bond critical points indicate the significant role of charge density fluctuations in the compounds studied. The 121, 123Sb NQR spin echo envelopes assigned to the ν1 transition (Δm = 1/2–3/2) were measured for the two crystallographic positions of Sb atoms in the Sb2S3 structure. Unexpectedly deep oscillations of NQR spin echo envelopes were observed in very small (1–3 Oe) external magnetic fields, evidencing for the existence of local magnetic fields in Sb2S3 similar to those earlier observed in bismuth oxide compounds.

The structure of near stoichiometric Ge-Ga-Sb-S glasses: A reverse Monte Carlo study

The structure of Ge22Ga3Sb10S65 and Ge15Ga10Sb10S65 glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) measurements at the Ge, Ga and Sb K-edges. Experimental data sets were fitted simultaneously in the framework of the reverse Monte Carlo (RMC) simulation technique. Short range order parameters were determined from the obtained large-scale configurations. It was found that the coordination numbers of Ge, Sb and S are around the values predicted by the Mott-rule (4, 3 and 2, respectively). The Ga atoms have on average 4 nearest neighbors. The structure of these stoichiometric glasses can be described by the chemically ordered network model: Ge-S, Ga-S and Sb-S bonds are the most important. Long Sb-S distances (0.3–0.4 Å higher than the usual covalent bond lengths) are observed, suggesting that Sb atoms can be found in various local environments.

Study of the Geometric Structures, Electronic and Magnetic Properties of Aluminium-Antimony Alloy Clusters

Abstract A joint investigation based on an unbiased CALYPSO structure searching method and density functional theory calculation is performed to obtain the most stable structures of the neutral and anionic Al n Sb (n = 1–16) clusters. The relative stability analysis reveals that the Al3Sb, Al5Sb, Al5Sb− and Al14Sb− clusters are more stable than their neighbouring clusters. The studies of electronic properties, especially in the consistency of the simulated photoelectron spectra and the experimental results for small clusters, further confirm that the predicted most stable structures are the global minima. Compared with pure aluminium (Al) clusters, the effect of impurity Sb atom on structural evolution of the neutral and anionic Al n Sb(n = 1–16) clusters may be neglected, revealing that the most stable structures can be obtained by replacing one Al atom with an Sb atom in the corresponding neutral and anionic Al n +1(n = 1–16) clusters except for 8, 11 and 12. Moreover, the discussion concerning the magnetic properties indicates that the 3p state of the Al atom in the neutral and anionic Al n Sb(n = 1–16) clusters is the main contributor to the total magnetic moment.

Shubnikov-de Haas oscillations of massive Dirac fermions in a Dirac antiferromagnet SrMnSb2

We investigate the physical properties of massive Dirac fermions in SrMnSb2 using transport, specific heat, electronic structure calculations, and Shubnikov-de Haas (SdH) oscillations. SrMnSb2 is a candidate Dirac antiferromagnet, consisting of the MnSb layers and the distorted square net of Sb atoms with a zigzag chain structure. This structural distortion leads to gap opening at the band crossing point found in the square lattice of the sister compound SrMnBi2 but leaves another Dirac band crossing near the Brillouin zone boundary. The small 2D Fermi surface with a light electron mass and a small Fermi energy is confirmed by the large resistivity anisotropy, the large Seebeck coefficient, and also the angle and temperature dependent SdH oscillations. The Berry phase obtained from the SdH oscillations is trivial, in contrast to the case of SrMnBi2. The relatively large spin orbit coupling gap and the small Fermi energy in SrMnSb2 is found to be essential to understand this contrasting behavior of the massive Dirac fermions as compared to SrMnBi2. Our observations demonstrate that the Berry phase of the mobile electrons in SrMnSb2 is sensitive to the Fermi level change and can be tuned by doping or deficiency.

Fabrication and electrical properties of Bi2-xSbxTe3 ternary nanopillars array films

Highly oriented Bi2-xSbxTe3 (x = 0, 0.7, 1.1, 1.5, 2) ternary nanocrystalline films were fabricated using vacuum thermal evaporation method. Microstructures and morphologies indicate that Bi2-xSbxTe3 films have pure rhombohedral phase with well-ordered nanopillars array. Bi, Sb and Te atoms uniformly distributed throughtout films with no precipitation. Electrical conductivity of Bi2-xSbxTe3 films transforms from n-type to p-type when x > 1.1. Metal-insulator transition was observed due to the incorporation of Sb in Bi2Te3. Bi2-xSbxTe3 film with x = 1.5 exhibits optimized electrical properties with maximum electrical conductivity σ of 2.95 × 105 S m−1 at T = 300 K, which is approximately ten times higher than that of the undoped Bi2Te3 film, and three times higher than previous report for Bi0.5Sb1.5Te3 films and bulk materials. The maximum power factor PF of Bi0.5Sb1.5Te3 nanopillars array film is about 3.83 μW cm−1 K−2 at T = 475 K. Highly oriented (Bi,Sb)2Te3 nanocrystalline films with tuned electronic transport properties have potentials in thermoelectric devices.

Crystal structures of antimony(III) chloride complexes with pyridine

Molecular structures of two new SbCl3–Py complexes, (SbCl3)4Py4 and (SbCl3)3Py5, in the solid state have been determined by single crystal X-ray diffraction. In both complexes all Sb atoms adopt a pseudo-octahedral coordination geometry which is completed by additional Sb⋯Cl contacts shorter than sum of van der Waals radii, with Cl–Sb⋯Cl angles close to 180°. These contacts indicate the presence of Sb⋯Cl pnictogen bonding. To reveal its nature, the DFT calculations were performed followed by the analyses of the electrostatic potentials, the orbital interactions and topological analysis.

Electrical properties and structural transition of Ge2Sb2Te5 adjusted by rare-earth element Gd for nonvolatile phase-change memory

Phase change memory has been considered as the next generation in non-volatile electronic data storage. The property modulation of such materials by the doping of rare-earth elements has drawn a lot of attention, which motivates us to search for the optimal dopants and reveal the underlying mechanisms. Here, we investigate the role of Gd as a dopant in Ge2Sb2Te5, which exhibits higher crystalline resistance and better thermal stability and antioxidant capacity than the undoped counterpart. Moreover, Gd dopants suppress both the processes of phase transition and grain growth. The crystalline structure remains unchanged with Gd dopants and vacancies are randomly distributed. Furthermore, the bonding mechanism was theoretically investigated. In the amorphous state, Gd atoms modify the local structures around Ge, Sb, and Te atoms. The large coordination number of Gd and the “Gd–Te distorted pentagonal bipyramidal-like” structure can be attributed to the good thermal stability. These microscopic findings figure out some of the key issues about the bonding mechanism, electrical properties, and crystallization behaviors of Gd doped phase change memory materials, which could be useful for storage devices.

Atomic scale insight into the effects of Aluminum doped Sb2Te for phase change memory application

To date, the unpleasant trade-off between crystallization speed and thermal stability for most phase change materials is detrimental to achieve phase change memory (PCM) with both features of high-speed and good-retention. However, it is proved that Al doping in Sb2Te, served as storage media in PCM, favors both a high writing speed (6 ns) and a good retention (103 °C), as well as a low power consumption. Judging by experimental and theoretical investigations, doped Al atoms prefer to replace Sb in Sb2Te lattice, strongly bonded with 6 Te atoms, to form a homogeneous phase. While in amorphous Al doped Sb2Te (AST), Al atoms are in tetrahedral environment, firmly bonded with four Sb/Te atoms. The strong bonding in Al centered tetrahedron in amorphous AST can obstruct the collective motion of Sb atoms near the matrix boundary, leading to the improvement in thermal stability and the confinement in grain size.

Effects of Addition of Si and Sb on the Microstructure and Thermoelectric Properties of GeTe

The effects of the addition of Si and Sb on the microstructure and thermoelectric properties of GeTe were investigated in this study. Pure GeTe showed a typical herringbone structure that consisted of regularly aligned domains with alternating bright and dark contrast areas. When Sb atoms were added to the GeTe, a clean herringbone structure was not formed. Instead, many sharp lines that are likely narrow domains were observed, and their formation can be ascribed to the cubic stabilizing nature of Sb in GeTe. The co-addition of Si and Sb to GeTe resulted in a breakdown of the herringbone structure and formation of SiGe and Si precipitates. Even though Si and Ge can form a complete solid solution, the solubility of Si in GeTe remained low. The addition of Sb to GeTe significantly reduced the electrical conductivity due to the aliovalent donor nature of Sb. Its thermal conductivity was also very low due to the mass fluctuation in the solid solution and narrow domain structure. Therefore, the best figure-of-merit (ZT) of 0.67 at 570 K was obtained. However, Ge1−x−ySbxSiyTe compounds with both Si and Sb addition showed a relatively low ZT value.

Effect of Sb substitution on structural and magnetic properties of MnBi based alloys

A series of MnBi1-xSbx alloys were prepared by a metallurgical method. The samples MnBi1-xSbx were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), vibrating-sample magnetometer (VSM). The effects of Sb substitution on the structural formation, electronic structure and magnetic property of MnBi were investigated experimentally and theoretically. We find that the introduction of Sb atoms may prevent the decomposition of Bi from MnBi, and thus help stabilize the low temperature phase (LTP) MnBi. In addition, first-principle calculations reveal that the saturation magnetization (Ms) and magnetic crystalline anisotropy constant (K) are increased upon increasing Sb-doping concentration, in contrast to a reduction of the Curie temperature (TC). Therefore, our findings could provide a promising route for enhancing the performance of MnBi permanent magnets.

Synthesis and Structures of Tris(3-Fluorophenyl)antimony Dicarboxylates: (3-FC6H4)3Sb[OC(O)R]2 (R = C6H3[(NO2)2-3,5)], CH2Br, CH2Cl, and CH=CHPh)

The reactions of tris(3-fluorophenyl)antimony (3-FС6H4)3Sb with 3,5-dinitrobenzoic, bromoacetic, chloroacetic, and cinnamic acids in the presence of tert-butyl hydroperoxide afford tris(3-fluorophenyl)antimony bis(3,5-dinitrobenzoate (I), tris(3-fluorophenyl)antimony bis(bromoacetate (II), tris(3-fluorophenyl)antimony bis(chloroacetate) (III), and tris(3-fluorophenyl)antimony dicinnamate (IV). According to the X-ray diffraction data, the coordination mode of the Sb atoms in all compounds is a trigonal bipyramid (CIF files CCDC nos. 1576022 (I), 1576023 (II), 1575287 (III), and 1576967 (IV). The axial angles OSbO are 174.70(6)°, 175.92(15)°, 176.62(6)°, and 175.81(11)°. The Sb−O and Sb−С bond lengths are 2.117(2), 2.137(2), and 2.105(3)−2.119(2) A in I; 2.110(4), 2.129(4), and 2.096(5)−2.112(5) A in II; 2.118(2), 2.136(2), and 2.120(2)−2.128(2) A in III; and 2.142(3) and 2.115(3)−2.119(4) A in IV. The Sb⋅⋅⋅O intramolecular distances with the carbonyl oxygen atom (2.895(3), 2.968(4) A (I); 2.814(6), 2.930(6) A (II); 2.809(3), 2.933(4) A (III); and 2.601(4) A (IV)) are shorter than the sum of the van der Waals radii of Sb and O by ∼1.0 A.

Atomic level structure of Ge-Sb-S glasses: Chemical short range order and long Sb-S bonds

The structure of Ge20Sb10S70, Ge23Sb12S65 and Ge26Sb13S61 glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements at the Ge and Sb K-edges as well as Raman scattering. For each composition, large scale structural models were obtained by fitting simultaneously diffraction and EXAFS data sets in the framework of the reverse Monte Carlo (RMC) simulation technique. Ge and S atoms have 4 and 2 nearest neighbors, respectively. The structure of these glasses can be described by the chemically ordered network model: Ge-S and Sb-S bonds are always preferred. These two bond types adequately describe the structure of the stoichiometric glass while S-S bonds can also be found in the S-rich composition. Raman scattering data show the presence of Ge-Ge, Ge-Sb and Sb-Sb bonds in the S-deficient glass but only Ge-Sb bonds are needed to fit diffraction and EXAFS datasets. A significant part of the Sb-S pairs has 0.3–0.4 Å longer bond distance than the usually accepted covalent bond length (∼2.45 Å). From this observation it was inferred that a part of Sb atoms have more than 3 S neighbors.

Tetrathiafulvalene Dimer Merged with a Binuclear Ring of Sn and Sb: Synthesis and Molecular Structures Induced by Heteroatoms

In this study, we describe the synthesis and characterization of dimeric tetrathiafulvalene (TTF) derivatives that are doubly bridged by Sn (1) and Sb (2a) atoms as a new class of organic‐inorganic hybrid compounds able to provide enhanced dimensionality in the solid state. The antimony heterocyclic framework was constructed by a simple Sn–Sb metal exchange reaction of a 1,4‐distannine moiety with p‐tolyl antimony dichloride (p‐tolSbCl2). Compound 2a was obtained in cis and trans forms as a stable configurational isomer. From X‐ray crystallographic analysis, there were three conformational isomers in which the tolyl rings were directed in the endo or exo direction. Crystal packing revealed a supramolecular three‐dimensional network through intermolecular short contacts of Sb···S and Sb···π. These packing forces gave a trans‐2aexo–exo conformation in the crystal, although the theoretical calculations predict its instability compared with other conformers. Cyclic voltammetry (CV) measurements of 1 and cis/trans‐2a revealed two pairs of reversible redox processes corresponding to the formation of TTF/TTF·+ and TTF·+/TTF2+. Furthermore, CV of cis/trans‐2a also revealed the reduction waves derived from the reduction of SbIII. Dicationic and tetracationic species were prepared by chemical oxidation, and their electronic structures were also investigated by electronic spectroscopy.

Mixing SbIIIand GeIVoccupancy in the polyoxovanadate {V14E8} archetype

AbstractThe first mixed germanato-antimonato derivative of the {V14E8O42} (E=semi-metal) cluster archetype has been synthesized under hydrothermal conditions and isolated as {Ni(phen)3}2[α-VIV14SbIII5GeIV3O42(OH)3(H2O)]· ≈16H2O (phen=1,10-phenanthroline). In the cluster anion, seven of the eight hetero-metal positions are occupied by disordered Ge/Sb atoms, while one position is fully occupied by Sb atoms. The [V14Sb5Ge3O42(OH)3(H2O)]6−anions are arranged in pairs with remarkably short inter-cluster Sb···O contacts. Bond valence sum calculation strongly suggests that the Sb···O contact must be taken into account as a weak bond. The magnetic properties are dominated by strong intra-cluster antiferromagnetic exchange interactions, and the cluster anion is magnetically quasi-isolated from the spins of the Ni2+complex cations.

Interfacial N→Sb Nonbonded Interaction Enhances the Photoelectronic Performance of PVP‐Capped Sb2S3 Amorphous Colloids

AbstractThe bonded or nonbonded interactions at the interface of ligands and surface atoms are a core issue in engineering the surface chemistry and (photo)electronic properties of semiconductor colloidal solids. Herein, we demonstrate the interfacial Lewis acid‐base N→Sb nonbonded interaction: N atoms in polyvinylpyrrolidone (PVP) molecules acting as an electron donor to enhance the photoconductivity and ‐responsivity of PVP‐capped Sb2S3 amorphous semiconductor colloids. The electron donation effect of PVP N atoms in the N→Sb interaction is backed by the upper shift of N 1s binding energy in the X‐ray photoelectron spectra (XPS) and the relevant literature. The repulsion of lone pair electrons (LPEs) of N atoms is thought to make 5 s2 LPEs of Sb atoms retract from Sb nuclei with an increased orbital volume, giving rise to high probability for the overlap and coupling of 5 s2 LPEs among neighboring Sb atoms on the surface of Sb2S3 amorphous colloids. Such a spatially and energetically matched electron‐electron coupling greatly contributes to the photoelectronic performance enhancement of amorphous Sb2S3. We believe that the electron coupling and improved (photo)electronics can be generalized in many semiconductors containing ns2 LPE metal cations by the surface/interface Lewis acid‐base interactions with suitable ligands.

Interaction between filler species in double-filled skutterudites

Filled skutterudites are workhorse materials in thermoelectric research. In recent years, double- or even triple-filling has emerged as a promising strategy to improve the thermoelectric figure of merit in skutterudites. For example, one type of filler is used to reduce thermal conductivity while the other filler is used to control the electron filling. However, in these studies, each filler atom is considered independent of each other and the interaction between the two filler atoms is completely ignored. Here we present our detailed investigation of the local structure of filler atoms in (${\mathrm{Yb},\mathrm{In})}_{x}{\mathrm{Co}}_{4}{\mathrm{Sb}}_{12}$ and show that significant interaction does exist between filler species. While Yb or In filler atoms at low concentration occupy the usual $2a$ filler site on their own, when Yb filler concentration goes above a critical value $x\ensuremath{\approx}0.15$, Yb pushes In atoms from the $2a$ site and into the $24g$ substitutional site replacing Sb atoms. This behavior is in stark contrast to that of Ga, which forms a dual-site defect even in the absence of Yb fillers. The temperature-dependent, extended x-ray absorption fine structure (EXAFS) data further reveal distinct lattice dynamical properties around In, Ga, and Yb filler atoms. Our findings point out that the filler interaction should be an important design consideration for new thermoelectric skutterudites.

Interactions between Sb and As on InAs(0 0 1) surfaces

Interfacial broadening that occurs due to intermixing of Sb and As at the interfaces is a challenge for growing high quality mixed anion heterostructures. In this work, we examine the atomic scale interaction between As and Sb. Experimental observations show that the surface consists primarily of (4 × 3) and c(4 × 4) reconstructions as a function of As and Sb overpressure. Density functional theory calculations confirm the experimental phase diagram and show that many of the reconstructions contain both Sb dimers and sub-surface Sb. This indicates concurrent mechanisms for interfacial broadening: some Sb atoms are weakly bound in dimer sites and segregate during growth, while some Sb atoms are driven to infiltrate the crystal and intermix with As. The calculations also predict a stoichiometric Sb-terminated α2(2 × 4) to be stable, suggesting that abrupt III-As/III-Sb heterostructures could be obtained by growing on this surface. While not trivial to achieve, this surface can be experimentally obtained by depositing Sb directly on an In-terminated surface.