Characterization of Sb2O3 subjected to different ion and plasma surface treatments

This paper presents a study of Sb₂O₃ subjected to oxygen plasma and to ion beam bombardment (Ar⁺ and O₂⁺ ions of 4 keV) by x‐ray photoelectron and reflected electron energy‐loss spectroscopies. Changes in stoichiometry (i.e O/Sb ratio) and oxidation state of Sb have been detected and correlated with the chemical and ballistic effects of the beams used for alteration of the Sb₂O₃ surface. Thus, oxygen plasma treatments lead to a significant oxidation of the surface layers of this material with the formation of up to 51% Sb⁵⁺ species as found by Sb 4d curve‐fitting analysis. By contrast, O₂⁺ ion bombardment only produces a mild oxidation of the target with the formation of ～13% Sb⁵⁺ species. Argon ion bombardment induces a complex process where Sb⁵⁺ and Sb⁰ species are formed simultaneously. This result has been discussed in terms of a disproportionation reaction of the type Sb³⁺ → Sb⁵⁺ + Sb⁰. The changes in the electronic properties of the treated material are consistent with the loss upon oxidation to Sb⁵⁺ of the valence states associated to the 5s² electron pair of antimony. Approximate shapes of valence bands for Sb₂O₃ and Sb₂O₅ pure compounds have been extracted by applying factor analysis to valence band spectra of Sb₂O₃ subjected to different ion and plasma treatments. Copyright © 2003 John Wiley & Sons, Ltd.     

Configurational Isomerism in Polyoxovanadates

A water‐soluble derivative of the polyoxovanadate {V₁₅E₆O₄₂} (E=semimetal) archetype enables the study of cluster shell rearrangements driven by supramolecular interactions. A reaction unique to E=Sb, induced exclusively by ligand metathesis in peripheral [Ni(ethylenediamine)₃]²⁺ counterions, results in the formation of the metastable α₁* configurational isomer of the {V₁₄Sb₈O₄₂} cluster type. Contrary to all other polyoxovanadate shell architectures, this isomer comprises an inward‐oriented vanadyl group and is ca. 50 and 12 kJ mol^?1 higher in energy than the previously isolated α and β isomers, respectively. We discuss this unexpected reaction in light of supramolecular Sb?O???V and Sb?O???Sb contacts manifested in {V₁₄Sb₈O₄₂}₂ dimers detected in the solid state. ESI MS experiments confirm the stability of these dimers also in solution and in the gas phase. DFT calculations indicate that other, as of yet elusive isomers of {V₁₄Sb₈}, might be accessible as well.     

Bis­[hydrogen 1,1′‐bis­(di­phenyl­phos­phinato)­ferrocenium] octa­chloro­diantimony(III)

In the title compound, [Fe(C₃₄H₂₉O₂P₂)]₂[Sb₂Cl₈], the discrete centrosymmetric [Sb₂Cl₈]^2? anions are formed from two edge‐shared square pyramids of Cl atoms about each Sb atom. Within the cation, the two di­phenyl­phosphinate groups share one H atom and the ferrocene cyclo­penta­dienyl rings are in a staggered conformation, with the average value of the twist angle being 46°. In the crystal, each [Sb₂Cl₈]^2? anion is involved in eight C—H?Cl interactions with four surrounding cations and these interactions interconnect the ions to form molecular columns along the a direction.     

Synthesis and solid state studies on Mb2Sb2O7 and (Mn1−xCdx)2Sb2O7 pyrochlores

Pyrochlore oxides of the type Mn₂Sb₂O₇ and (Mn_1?xCd_x)₂Sb₂O₇ have been synthesized by high-temperature solid state reactions and characterized by X-ray diffraction and chemical analysis. X-Ray diffraction studies showed that the compound Mn₂Sb₂O₇ has a rhombohedrally distorted pyrochlore structure. In the solid solutions (Mn_1?xCd_x)₂Sb₂O₇, the phases with x ≥ 0.6 are cubic. Magnetic and ¹²¹Sb Mössbauer studies indicate that all the Mn and Sb are present in the +2 and +5 state occupying A and B sites, respectively, in the pyrochlore structure. Electrical measurements indicate that the compounds are insulators or semiconductors exhibiting p-type behavior. The stoichiometry and probable cause of the rhombohedral distortion in Mn₂Sb₂O₇ and solid solutions are discussed.     

Selective extraction of traffic-related antimony compounds for speciation analysis by graphite furnace atomic absorption spectrometry

Most traffic-related antimony air pollutants are derived from brake dust. Brake dust contains Sb₂S₃, used as a friction material in brake pads, and its high-temperature oxidation products, Sb₂O₃ or Sb₂O₄. Systematic investigations were carried out to find the most selective leaching conditions for these substances. First, solubility experiments of the pure potential compounds mentioned above were carried out. Then, the leaching of these compounds from home-made artificial dusts previously spiked with these compounds at the trace level was investigated. A 0.5 mol L^?1 citric acid solution proved to leach the whole Sb₂O₃ content while extracting less than 10% Sb₂S₃ and no Sb₂O₄ at all. It was found that Sb₂O₃ and Sb₂S₃ traces were soluble in a 6 mol L^?1 HCl solution, quantitatively and selectively. Graphite furnace atomic absorption spectrometry and hydride generation graphite furnace atomic absorption spectrometry methods were developed to determine the Sb content of the extracts. The proposed method proved to be applicable to settled dust containing traffic-related Sb compounds. The detection limits were 1.2 and 0.3 μg g^?1 for leaching by citric acid and HCl solution, respectively, which were adequate for Sb content determination in the urban dust studied. The reproducibility of the method expressed as relative standard deviation was about 7%. The results showed that the concentration of leachable Sb was 40 μg g^?1 in the settled dust of Budapest, about half of which corresponded to Sb₂O₃. The Sb₂O₄ content calculated as the difference of total and leachable fraction was about 10% with high uncertainty.     

Hydrolysis of antimony(III) fluoride complexes

Vibrational and ¹⁷O NMR spectroscopy in combination with quantum chemical calculations are used to investigate the hydrolysis of antimony(III) fluoride complexes. A hydrolytic decomposition of SbF₃ and [SbF₄]^? is accompanied by oligomerization with the formation of edge-and corner-connected dimers ([Sb₂O₂F₄]^2?, [Sb₂OF₈]^4?) and trimers ([Sb₃O₃F₆]^3?, [Sb₃OF₉]^2?) with bridging oxygen atoms. The hydrolysis of [SbF₄]^? is also characterized by the presence in the solution of a discrete cation of [SbF₅]^2? which is least hydrolized. Only a partial isomorphic substitution of fluoride ion by hydroxide one is possible, which is reflected in the composition of K₂Sb(OH)_xF_5?x (x = 0.3) crystals isolated from the fluoride aqueous solution.     

d,h-m̈-Alkoxoalkylphosphonato-e-m̈-alkoxo-f-m̈-oxo-bis[trichloroantimon(V)]-Verbindungen

d,h-m?-Alkoxoalkylphosphonato-e-m?-alkoxo-f-m?-oxo-bis[trichloroantimony(V)] Compounds The binuclear antimony(V) complexes Cl₃Sb(O)[R³(R¹O)PO₂](OR²)SbCl₃ 1 to 7 with R¹, R² and R³ = Me or Et in solution slowly exchanges the R² groups between the equatorial oxygen atoms of the Sb₂O₂ ring. The SbO(3)PO(3)Sb ringsystem makes rapid pseudorotation. The resulting isomeres are detected by nmr spectroscopy.     

New materials synthesis: Characterization of some metal-doped antimony oxides

In order to understand the chemistry of altermetal dopants in antimony oxide, the detailed structural characterization of two β-Sb₂O₄ compounds is reported, Mo-doped β-Sb₂O₄ (1.5 metal%) and V-doped β-Sb₂O₄ (5 metal%). The methods used to characterize these materials are X-ray and neutron diffraction, scanning electron microscopy, Mo K-edge extended X-ray absorption fine structure spectroscopy, and elemental analysis. The atomic position of each of these dopants in Sb₂O₄ is radically different as is the overall effect on the host structure. Molybdenum does not substitute for Sb atoms, rather the Mo atoms are found in channels of electron density formed by Sb³⁺ lone pairs. The two nearest Sb³⁺ are absent and the oxygen stoichiometry is preserved. The formula is Sb_1.97Mo_0.015O₄. Vanadium incorporates substitutionally for the Sb³⁺ atoms and there are random oxygen vacancies in the resultant structure. The formula is Sb_1.9V_0.1O_3.67. In each case the atomic positions of the host structure (Sb and O) are remarkably unaltered. The β-Sb₂O₄ structure can accommodate Mo and V simultaneously, presumably both means of metal incorporation are employed in this ternary oxide.     

The oxidation state of antimony and electrical properties in antimony-doped rutile

The reaction of TiO₂ with Sb₂O₄ for temperatures in the range of 650 to 1000°C indicates that Sb can dissolve in rutile up to the proportion of 7 mole% in an Sb₂O₄ equivalent. With increasing content of Sb, the unit cell volume increased gradually. From the results on the binding energies of 530.6 eV forSb(3d₃₂) and 540.1 eV forSb(3d₅₂), it is expected that Sb was substituted as Sb³⁺ ion for Ti⁴⁺ in the rutile structure. Theac resistivities of rutile with Sb are in the range of 10² to 10⁵ ohm · m at room temperature. The frequency and temperature dependencies of the dielectric constant can be elucidated by the ionic polarization model coupling Sb with oxygen vacancy. The activation energy, giving a loss maximum, was determined to be 0.15–0.17 eV over a frequency range of 10⁴ to 10⁷ Hz.     

Element-Element-Bindungen. VI. Kristallines 2-Chlor-1,3,2-benzoxathiastibol – ein mehrfach verknüpftes Koordinationspolymeres

Element-Element-Bonds. VI. Crystalline 2-Chloro-1,3,2-benzoxathiastibole – a Multiply Linked Coordination Polymer Yellow 2-chloro-1,3,2-benzoxathiastibole 4a first prepared by Anchisi and coworkers [3] from o-hydroxythiophenol and antimony trichloride, crystallizes in the monoclinic space group P2₁/n {a = 1109.9(3); b = 610.5(2); c = 1201.5(2) pm; β = 100.35(2)° at ?120 ± 3°C; Z = 4}. An X-ray structure determination (R = 0.029) shows the molecules to form coordination polymeric layers via Sb…?Cl, Sb…?O and Sb…?η²-arene interactions in the solid. Characteristic structural features are Sb? Cl…?Sb? Cl helices (Sb? Cl…?Sb 119°; Cl? Sb…?Cl 95°) and centrosymmetric, four membered Sb₂O₂-rings (O? Sb…?O 64°; Sb? O…?Sb 116°). The ligands set up a strongly distorted octahedron around the antimony atom: Sb? S 242; Sb? Cl 243; Sb…?Cl 328; Sb? O 201; Sb…?O 287; Sb…?C 338 and 341 pm; S? Sb? O 85°; S? Sb? Cl 94°; O? Sb? Cl 92°.     

Darstellung und Kristallstruktur von CsSb2Se4

Preparation and Crystal Structure of CsSb₂Se₄ CsSb₂Se₄ was prepared by hydrothermal reaction of Cs₂CO₃ with Sb₂Se₃ at a temperature of 115°C. An X-ray structural analysis demonstrated that the compound contains polyselenoantimonate(III) anions (Sb₂Se₄^?)_n, which display both (Sb)Se? Sb and (Sb)Se? Se(Sb) bridges. A ψ-tetrahedral coordination is observed for one of the independent Sb atoms, a ψ-trigonal bipyramidal coordination for the other. The Sb? Se polyhedra are linked through joint corners and edges and in addition via direct Se? Se bonds into sheets.     

High Nuclearity Antimonato‐Polyoxovanadate Cluster {V15Sb6O42} as a Synthon for the Solvothermal in situ Generation of α‐ and β‐{V14Sb8O42} Isomers

New heteroatom polyoxovanadates (POVs) were synthesized by applying a water‐soluble high‐nuclearity cluster as new synthon. The [V₁₅Sb₆O₄₂]^6? cluster shell exhibiting D₃ symmetry was in situ transformed into completely different cluster shells, namely, the α‐[V₁₄Sb₈O₄₂]^4? isomer with D_2d and the β‐[V₁₄Sb₈O₄₂]^4? isomer with D_2h symmetry. The solvothermal reaction of {Ni(en)₃}₃[V₁₅Sb₆O₄₂(H₂O)_x] ? 15 H₂O (x=0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en)₂}₂V₁₄Sb₈O₄₂] ? 5.5 H₂O containing the β‐isomer. The addition of [Ni(phen)₃](ClO₄)₂ ? 0.5 H₂O (phen=1,10‐phenanthroline) to the reaction slurry gave the new compound {Ni(phen)₃}₂[V₁₄Sb₈O₄₂] ? phen ? 12 H₂O with the α‐isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO₅ square pyramids and Sb₂O₅ handle‐like moieties.     

Raman spectroscopy study of species responsible for the fast proton conductivity in H2Sb4O11.3H2O

The Raman spectroscopy study of crystallized antimonic acid trihydrate powders in the 20–4000 cm⁻¹ confirme the explicit formula : (H₃O⁺)_2−x[Sb₄O_11−xOH_x]^−(2−x).(3+x−2)H₂O. Furthermore it emphasizes the presence of hydrogen bonds between either the SbOSb bridge and H₃O⁺ or the protonated Sb(OH)Sb bridge and H₂O.     

Composition and Crystal Structure of SmSb2O4Cl Revisited – and the Analogy of Sm1.5Sb1.5O4Br

The quaternary halide‐containing samarium(III) oxidoantimonates(III) Sm_1.3Sb_1.7O₄Cl and Sm_1.5Sb_1.5O₄Br were synthesized through solid‐state reactions from the binary components (Sm₂O₃, Sb₂O₃ and SmX₃, X = Cl and Br) at 750 °C in evacuated fused silica ampoules. They crystallize tetragonally in the space group P4/mmm, like the basically isotypic bismuthate(III) compounds SmBi₂O₄Cl and SmBi₂O₄Br, but show larger molar volumes and therefore contradict an ideal composition of “SmSb₂O₄X” (X = Cl and Br). Both single‐crystal X‐ray diffraction and quantitative electron‐beam microprobe analysis revealed the actual compositions of the investigated antimony(III) compounds, which can be understood as heavily Sm³⁺‐doped derivatives of “SmSb₂O₄X” hosts at the Sb³⁺ site. (Sm1)³⁺ is coordinated eightfold by oxygen atoms in the shape of a cube. The mixed‐occupied (Sb/Sm2)³⁺ cation has four oxygen atoms and four halide anions as neighbors forming a square antiprism. The oxygen atoms and anions establish alternating layers parallel to the ab‐plane, which alternate when stacked along [001].     

The Rb7Bi3−3xSb3xCl16 Family: A Fully Inorganic Solid Solution with Room‐Temperature Luminescent Members

Low‐dimensional ns²‐metal halide compounds have received immense attention for applications in solid‐state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb²⁺ or unstable Sn²⁺, and a stable inorganic luminescent material has yet to be found. Here, the zero‐dimensional Rb₇Sb₃Cl₁₆ phase, comprised of isolated [SbCl₆]^3? octahedra and edge‐sharing [Sb₂Cl₁₀]^4? dimers, shows room‐temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature‐dependent PL lifetime rivals that of previous low‐dimensional materials with a specific temperature sensitivity above 0.06 K^?1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi³⁺ in the Rb₇Bi_3?3xSb_3xCl₁₆ (x≤1) family, we present the edge‐shared [Sb₂Cl₁₀]^4? dimer as a design principle for Sb‐based luminescent materials.     

Samarium Polystibides Derived from Highly Activated Nanoscale Antimony

Zintl ions in molecular compounds are of fundamental interest for basic research and application. Two reactive antimony sources are presented that allow direct access to molecular polystibide compounds. These are Sb amalgam (Sb/Hg) and ultrasmall Sb⁰ nanoparticles (d=6.6±0.8 nm), which were used independently as precursors for the synthesis of the largest f‐element polystibide, [(Cp*₂Sm)₄Sb₈]. Whereas the reaction of the nanoparticles with [Cp*₂Sm] directly led to [(Cp*₂Sm)₄Sb₈], Sm/Sb/Hg intermediates were isolated when using Sb/Hg as the precursor. These Sm/Sb/Hg intermediates [{(Cp*₂Sm)₂Sb}₂(μ‐Hg)] and [{(Cp*₂Sm)₃(μ⁴,η^1:2:2:2‐Sb₄)}₂Hg] were synthetically trapped and structurally characterized, giving insight in the formation mechanism of polystibide compounds.     

A 3D Hybrid Praseodymium–Antimony–Oxochloride Compound: Single‐Crystal‐to‐Single‐Crystal Transformation and Photocatalytic Properties

A 3D organic–inorganic hybrid compound, (2‐MepyH)₃ [{Fe(1,10‐phen)₃}₃][{Pr₄Sb₁₂O₁₈(OH) Cl_11.5}(TDC)_4.5({Pr₄Sb₁₂O₁₈(OH)Cl_9.5} Cl)] ? 3 (2‐Mepy) ? 28 H₂O ( 1 ; 2‐Mepy=2‐methylpyridine, 1,10‐phen=1,10‐phenanthroline, H₂TDC=thiophene‐2,5‐dicarboxylic acid), was hydrothermally synthesized and structurally characterized. Unusually, two kinds of high‐nuclearity clusters, namely [(Pr₄Sb₁₂O₁₈ (OH)Cl₁₁)(COO)₅]^5? and [(Pr₄Sb₁₂O₁₈ (OH)Cl₉)Cl(COO)₅]^4?, coexist in the structure of compound 1 ; two of the latter clusters are doubly bridged by two μ₂‐Cl^? moieties to form a new centrosymmetric dimeric cluster. An unprecedented spontaneous and reversible single‐crystal‐to‐single‐crystal transformation was observed, which simultaneously involved a notable organic‐ligand movement between the metal ions and an alteration of the bridging ion in the dimeric cluster, induced by guest‐release/re‐adsorption, thereby giving rise to the interconversion between compound 1 and the compound (2‐MepyH)₃[{Fe(1,10‐phen)₃}₃][{Pr₄Sb₁₂O₁₈(OH)Cl_11.5}(TDC)₄({Pr₄Sb₁₂O₁₈Cl_10.5(TDC)_0.5(H₂O)_1.5}O_0.5)] ? 25 H₂O ( 1′ ). The mechanism of this transformation has also been discussed in great detail. Photocatalytic H₂‐evolution activity was observed for compound 1′ under UV light with Pt as a co‐catalyst and MeOH as a sacrificial electron donor.     

Die Kristallstrukturen von (DDI)2[Sb2F6O] und (DDI)2[Sb3F7O2] (DDI = 1, 3‐Diisopropyl‐4, 5‐dimethylimidazolium) — Ein Beitrag zur Hydrolyse von SbF3 [1]

The Crystal Structures of (DDI)₂[Sb₂F₆O] and (DDI)₂[Sb₃F₇O₂] (DDI = 1,3‐Diisopropyl‐4,5‐dimethylimidazolium) — a Contribution to the Hydrolysis of SbF₃ [1] The salts (DDI)₂[Sb₂F₆O] ( 2 ) and (DDI)₂[Sb₃F₇O₂] ( 3 ), (DDI = 1,3‐diisopropyl‐4,5‐dimethylimidazolium) are obtained by hydrolysis of C₁₁H₂₀N₂SbF₃ ( 1 ). The anion [Sb₂F₆O]^2? consists of two SbF₂ fragments linked by a symmetrical oxygen bridge and two unsymmetrical fluorine bridges to form a distored ψ‐octahedral coordination sphere at the antimony atoms. In [Sb₃F₇O₂]^2?, two SbF₂ units are linked by a symmetrical fluorine bridge, while the third antimony atom is connected with each SbF₂ fragment by a symmetrical oxygen and an unsymmetrical fluorine bridge. The antimony atoms adopt the centres of strongly distored ψ‐polyhedra.     

{[CuSn5Sb3]2−}2: A Dimer of Inhomogeneous Superatoms

Reaction of the binary Zintl anion (Sn₂Sb₂)^2? with the β‐diketiminato complex [LCu(NCMe)] (L=nacnac=[(N(C₆H₃ⁱPr₂‐2,6)C(Me))₂CH]^?) in ethylenediamine or DMF affords the ternary cluster dimer {[CuSn₅Sb₃]^2?}₂ ( 1 ) as its [K(crypt‐222)]⁺ salt. The chemical formulation of 1 is supported by energy‐dispersive X‐ray spectroscopy (EDX) and quantum chemical calculations. Each monomeric part of the dimer represents a trimetallic “[CuSn₅Sb₃]^2?” cluster, with an architecture in between a tricapped trigonal prism and a capped square antiprism. As shown by quantum chemical investigations, the presence of Sb atoms and, in particular, of Cu atoms in the cluster skeleton makes the monomeric unit behave like an inhomogeneous superatom, which clearly prefers to dimerize, thereby producing a relatively short, yet virtually non‐bonding Cu???Cu distance.     

Synthesis and Structural Characterization of Magnesium‐Substituted Polystibides [(LMg)4Sb8]

Redox reactions of [(L^1,2Mg)₂] and Sb₂R₄ (R=Me, Et) yielded the first Mg‐substituted realgar‐type Sb₈ polystibides [(L^1,2Mg)₄(μ₄,η^2:2:2:2‐Sb₈)] (L¹=HC[C(Me)N(2,4,6‐Me₃C₆H₂)]₂, L²=HC[C(Me)N(2,6‐i‐Pr₂C₆H₃)]₂). Compounds [(L^1,2Mg)₂] serve both as reducing agents, initiating the cleavage of the Sb?C bonds, and as stabilizers for the resulting Sb₈ polyanion. The polystibides were characterized by NMR and IR spectroscopies, elemental analysis, and X‐ray structure analysis. In addition, results from quantum chemical calculations are presented.