Preparation,crystal structure,and infrared characterization of the first thiocyanato-oxy-antimonate(III) [(CH3)4N]2[Sb6O4(NCS)12]

The salt [(CH₃)₄N]₂[Sb₆O₄(NCS)₁₂] is the first identified thiocyanato-oxy-antimonate(III) complex. Reported are details of the synthesis, relevant infrared data and its x-ray structure. The compound crystallizes in the triclinic space group P1 with Z = 2 (C₁₀H₁₂N₇O₂S₆Sb₃) and unit cell dimensions a = 11.314(6), b = 12.846(3), c = 8.679(2) Å; α = 91.93(3)°, β = 90.31(3)° and γ = 99.13(3)°. It contains centrosymmetric [Sb₆O₄(NCS)₁₂]^2? anions packed with isolated tetramethyl-ammonium cations. The fundamental structural element of the anion is provided by the fusion of three SbOSbO rings forming a zig-zag portion of a ribbon, only slightly pleated. Peculiar is the unequivalence of the six thiocyanate ligands, though all primarily N-bonded to antimony atoms. Three thiocyanates are terminal while other three are asymmetrically N-bridging between two centers; two of this latter type are also interconnecting the anions via Sb???S contacts. There are three different antimony environments, the primary bonding at Sb being to one nitrogen and three oxygens, to one oxygen and three nitrogens and to two atoms of each type.     

Ge Pairs and Sb Ribbons in Rare‐Earth Germanium Antimonides RE12Ge7−xSb21 (RE=La–Pr)

The ternary rare‐earth germanium antimonides RE₁₂Ge_7?xSb₂₁ (RE=La–Pr; x=0.4–0.5) are synthesized by direct reactions of the elements. Single‐crystal X‐ray diffraction studies indicate that they adopt a new structure type (space group Immm, Z=2, a=4.3165(4)–4.2578(2) Å, b=15.2050(12)–14.9777(7) Å, c=34.443(3)–33.9376(16) Å in the progression from RE=La to Pr), integrating complex features found in RE₆Ge_5?xSb_11+x and RE₁₂Ga₄Sb₂₃. A three‐dimensional polyanionic framework, consisting of Ge pairs and Sb ribbons, outlines large channels occupied by columns of face‐sharing RE₆ trigonal prisms. These trigonal prisms are centered by additional Ge and Sb atoms to form GeSb₃ trigonal‐planar units. A bonding analysis attempted through a Zintl–Klemm approach suggests that full electron transfer from the RE atoms to the anionic substructure cannot be assumed. This is confirmed by band‐structure calculations, which also reveal the importance of Ge? Sb and Sb? Sb bonding. Magnetic measurements on Ce₁₂Ge_6.5Sb₂₁ indicate antiferromagnetic coupling but no long‐range ordering down to 2 K.     

[Sb(12-Krone-4)2(CH3CN)][SbCl6]3 und [Bi(12-Krone-4)2(CH3CN)][SbCl6]3, die ersten Trikationen von Antimon(III) und Bismut(III)

[Sb(12-Crown-4)₂(CH₃CN)][SbCl₆]₃ and [Bi(12-Crown-4)₂(CH₃CN)][SbCl₆]₃, first Trications of Antimony(III) and Bismuth(III) The crown ether complexes [M(12-crown-4)₂(CH₃CN)][SbCl₆]₃ with M = Sb and Bi are formed by the reaction of antimony trichloride and bismuth trichloride, respectively, with antimony pentachloride in acetonitrile solution in the presence of 12-crown-4. They form colourless, moisture sensitive crystals, which were characterized by X-ray structure determinations and by IR spectroscopy. The complex with M = Sb was also characterized by ¹²¹Sb Mössbauer spectroscopy. Both complexes crystallize isotypically in the orthorhombic space group Pbcn with four formula units per unit cell. M = Sb: 3 483 observed unique reflections, R = 0.038. M = Bi: 2 958 observed unique reflections, R = 0.036. The compounds consist of SbCl₆^? ions and trications [M(12-crown-4)₂(CH₃CN)]³⁺, in which the M³⁺ ions are ninefold coordinated by the eight oxygen atoms of the crown ether molecules and by the nitrogen atom of the acetonitrile molecule. The lone pair of the M³⁺ ions has no steric effect.     

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.     

Pentabromothio-diarsenat und -diantimonat: Darstellung,Schwingungsspektren und Kristallstrukturen von PPh4[As2SBr5] und PPh4[Sb2SBr5]

Pentabromothio-diarsenate and -diantimonate: Preparation, Vibrational Spectra, and Crystal Structures of PPh₄[As₂SBr₅] and PPh₄[Sb₂SBr₅] The title compounds were obtained in CH₂Br₂ from PPh₄Br, HBr and As₂S₃ or Sb₂S₃, respectively. Their i.r. and Raman spectra are reported. Their crystal structures were determined by X-ray diffraction. Crystal data: PPh₄[As₂SBr₅], monoclinic, space group P2₁/n, Z = 4, a = 1192.3, b = 1528.1, c = 1618.0 pm, β = 95.53°, isotypic with PPh₄[As₂SCl₅] (structure determination with 1539 observed reflexions, R = 0.052); PPh₄[Sb₂SBr₅], triclinic, space group P1 , Z = 2, a = 1044,8, b = 1207.1, c = 1307.8 pm, α = 104.77, β = 108.63, γ = 98.34° (2398 observed reflexions, R = 0.032). Both ions, [As₂SBr₅]^? and [Sb₂SBr₅]^?, have the same general structure: including the lone electron pairs, the As and Sb atoms have distorted trigonal-bipyrimidal coordination, two bipyramids sharing a common edge with sulfur and bromine as bridging atoms. The [As₂SBr₅]^? ions are associated to chains via As…Br contacts, the [Sb₂SBr₅]^? ions form pseudodimeric units by Sb…S and Sb…Br contacts. Whereas the crystal packing of the As compound is similar to that of other PPh₄⁺ compounds having a cation to anion ratio of 1:1, the Sb compound shows the packing principle known for 2:1 compounds.     

Grenzfälle des Zintl-Konzepts Zur Kenntnis von Ba7Ga4Sb9

On the Limits of the Zintl Concept. The New Compound Ba₇Ga₄Sb₉ The new compound Ba₇Ga₄Sb₉ crystallizes in the orthorhombic system, space group Pmmn (No. 59) with the lattice constants GaSb₄ tetrahedra are connected by common corners and edges to strings, which are connected by long Sb? Sb bonds to sheets, separated by the Ba ions. The compound is not in accordance to the Zintl concept.     

Crystal Structure and Properties of Some Filled and Unfilled Skutterudites: GdFe4P12, SmFe4P12, NdFe4As12, Eu0.54Co4Sb12, Fe0.5Ni0.5P3, CoP3, and NiP3

The new cubic compound Fe_0.5Ni_0.5P₃ (a = 775.29(5) pm) as well as the known compounds CoP₃ and NiP₃ were synthesized from the elemental components using tin as a flux. Their skutterudite (CoAs₃) type structures were refined from single‐crystal X‐ray data. The new compound GdFe₄P₁₂ was prepared by reaction of an alloy Gd_1/3Fe_2/3 with phosphorus in a tin flux. Its cubic “filled” skutterudite (LaFe₄P₁₂ type) structure was refined from single‐crystal X‐ray data: a = 779.49(4) pm, R = 0.019 for 304 structure factors and 11 variable parameters. SmFe₄P₁₂ shows Van Vleck paramagnetism while GdFe₄P₁₂ is a soft ferromagnet with a Curie temperature of T_C = 22(5) K. Both are metallic conductors. The new isotypic polyarsenide NdFe₄As₁₂ (a = 830.9(1) pm) was obtained by reacting NdAs₂ with iron and arsenic in the presence of a NaCl/KCl flux. The new isotypic polyantimonide Eu_0.54(1)Co₄Sb₁₂ (a = 909.41(8) pm) was prepared by reaction of EuSb₂ with cobalt and antimony. Its structure was refined from single‐crystal X‐ray data to a residual of 0.024 (137 F values, 12 variables). A comparison of the Fe–P and P–P bond lengths in the compounds AFe₄P₁₂, where the A atoms (A = Ce, Eu, Gd, Th) have differing valencies, suggests that the Fermi level cuts through Fe–P bonding and P–P antibonding bands.     

Synthese und Kristallstrukturen der Thiochloroantimonate(III) PPh4[Sb2SCl5] und (PPh4)2[Sb2SCl6] · CH3CN

Syntheses and Crystal Structures of the Thiochloroantimonates(III) PPh₄[Sb₂SCl₅] and (PPh₄)₂[Sb₂SCl₆]. CH₃CN (PPh₄)₂Sb₃Cl₁₁, obtained from Sb₂S₃, PPh₄Cl and HCl, reacts with Na₂S₄ in acetonitrile forming PPh₄[Sb₂SCl₅]. From this and Na₂S₄ or from (PPh₄)₂[Sb₂Cl₈] and Na₂S₄ or K₂S₅ in acetonitrile (PPh₄)₂[Sb₂SCl₆] · CH₃CN is obtained. Data obtained from the X-ray crystal structure determinations are: PPh₄[Sb₂SCl₅], monoclinic, space group P2₁/c, a = 1002.9(3), b = 1705.6(5), c = 1653.7(5) pm, β = 99.12(2)°, Z = 4, R = 0.068 for 1283 reflextions; (PPh₄)₂[Sb₂SCl₆] · CH₃CN, triclinic, space group P1 , a = 1287.8(7), b = 1343.6(9), c = 1696.5(9) pm, α = 69.82(5), β = 85.08(4), γ = 71.54(6)°, Z = 2, R = 0.059 for 6409 reflexions. In every anion two Sb atoms are linked via one sulfur and one ore two chloro atoms, respectively. Paris of [SbSCl₅]^? ions are associated via Sb …? S and Sb …? Cl contacts forming dimer units. In both compounds every Sb atom has a distorted octahedral coordination when the lone electron pair is included in the counting.     

(n‐Nitrophenyl)acetonitrile,with n = 2, 3 and 4

The molecular structures of the three title nitro‐substituted phenyl­aceto­nitriles, C₈H₆N₂O₂, at 123 K show that the mol­ecules are linked together very differently. In the 2‐ and 4‐nitro compounds, there are both O?H and N_cyano?H interactions, whereas the crystal lattice of the 3‐nitro compound is essentially built up by O?H interactions. The O atoms seem to prefer the aromatic H atoms, while the cyano N atoms prefer the methyl­ene H atoms. The phenyl–nitro torsion angles are ?19.83 (13), ?5.69 (12) and ?2.88 (12)°, while the phenyl–cyano­methyl torsion angles are ?62.27 (12), ?147.99 (9) and ?16.75 (14)° in the 2‐, 3‐ and 4‐NO₂‐substituted compounds, respectively.     

Ternary rare-earth titanium antimonides: Phase equilibria in the RE-Ti-Sb (RE=La, Er) systems and crystal structures of RE2Ti7Sb12 (RE=La, Ce, Pr, Nd) and RETi3(SnxSb1-x)4 (RE=Nd, Sm)

Investigations on phase relationships and crystal structures have been conducted on several ternary rare-earth titanium antimonide systems. The isothermal cross-sections of the ternary RE-Ti-Sb systems containing a representative early (RE=La) and late rare-earth element (RE=Er) have been constructed at 800 °C. In the La-Ti-Sb system, the previously known compound La₃TiSb₅ was confirmed and the new compound La₂Ti₇Sb₁₂ (own type, Cmmm, Z=2, a=10.5446(10) Å, b=20.768(2) Å, and c=4.4344(4) Å) was discovered. In the Er-Ti-Sb system, no ternary compounds were found. The structure of La₂Ti₇Sb₁₂ consists of a complex arrangement of TiSb₆ octahedra and disordered fragments of homoatomic Sb assemblies, generating a three-dimensional framework in which La atoms reside. Other early rare-earth elements (RE=Ce, Pr, Nd) can be substituted in this structure type. Attempts to prepare crystals in these systems through use of a tin flux resulted in the discovery of a new Sn-containing pseudoternary phase RETi₃(Sn_xSb_1−x)₄ for RE=Nd, Sm (own type, Fmmm, Z=8; a=5.7806(4) Å, b=10.0846(7) Å, and c=24.2260(16) Å for NdTi₃(Sn_0.1Sb_0.9)₄; a=5.7590(4) Å, b=10.0686(6) Å, and c=24.1167(14) Å for SmTi₃(Sn_0.1Sb_0.9)₄). Its structure consists of double-layer slabs of Ti-centred octahedra stacked alternately with nets of the RE atoms; the Ti atoms are arranged in kagome nets.     

Partial Cu occupancy in uranium copper diantimonide,UCu0.60(4)Sb2

The title compound, UCu_0.60(4)Sb₂, crystallizes in the tetragonal space group P4/nmm. The U atom and one independent Sb atom have 4mm site symmetry, whereas the Cu atom and the other Sb atom have 2m site symmetry. Zigzag USb sheets stack perpendicular to the c axis. These sheets are separated by square‐planar nets of Sb atoms and Cu atoms. The length of the a axis for UCu_xSb₂ is invariant to x, whereas there is a linear relationship between Cu occupancy and the length of the c axis (following Vegard's Law) that holds for x between 0 and 1. This is explained in terms of the crystal structure.     

Exploring LiZnNbO4 as a Host for New Colored Compounds: Synthesis,Structure, and Material Properties of NbZn1-x Mx LiO4 (M=Mn,Co, Ni,Fe) and Nb1-ySby Zn1-x Mx LiO4 (M=Co,Ni)

The non - centrosymmetric tetragonal inverse spinel structure of LiZnNbO₄ has been explored with a view to prepare new colored compounds. The substitution of Co²⁺, Ni²⁺, Fe²⁺, Mn²⁺, and Cu²⁺ ions were attempted in the place of Zn²⁺ ions and Sb⁵⁺ ions in place of Nb⁵⁺ ions. The studies indicated that 0.75 Zn²⁺ ions in LiZnNbO₄ can be replaced by Co²⁺ ions and 0.5 Zn²⁺ ions in LiZnNb_0.5Sb_0.5O₄ compound. The substitution of Co²⁺ ions gives rise to different shades of blue color in Li(Zn_1-xCo_x)NbO₄ compounds and from ink blue to blue-green color in Li(Zn_1-xCo_x)(Nb_0.5Sb_0.5)O₄ compounds. The different colors observed in the present study were explained by the traditional allowed d-d transitions as well as the metal-to-metal charge transfer (MMCT) transitions involving Nb⁵⁺ (4d⁰) ions and partially filled 3d electrons. The SHG studies indicate that the prepared compounds are SHG active. All the compounds exhibit reasonable dielectric behavior with low loss. The XPS studies confirm the oxidation states of the different substituted ions. Raman studies indicate variations in the bands due to the substitutions in the parent LiZnNbO₄ phase. Magnetic studies on the Co²⁺ ions substituted compounds suggest antiferromagnetic behavior.     

Ba5Ti12Sb19+x, a polar intermetallic compound with a stuffed γ-brass structure

The polar intermetallic compound Ba₅Ti₁₂Sb_19+x (x0.2) has been synthesized by reaction of the elements. Single-crystal X-ray diffraction analysis revealed that it adopts a new structure type (Ba₅Ti₁₂Sb_19.102(6), space group , Z=2, a=12.4223(11) Å, V=1916.9(3) Å³). The set of Ba and Sb sites corresponds to the structure of Cu₉Al₄, a γ-brass type with a primitive cell. A complex three-dimensional framework of Ti atoms, in the form of linked planar Ti₉ clusters, is stuffed within the γ-brass-type Ba–Sb substructure. Notwithstanding its relationship to the γ-brass structure, the compound does not appear to conform to the Hume–Rothery electron concentration rules. Band structure calculations on an idealized Ba₅Ti₁₂Sb₁₉ model suggest that the availability of bonding states above the Fermi level is responsible for the partial occupation, but only to a limited degree, of an additional Sb site within the structure. Magnetic measurements indicated Pauli paramagnetic behaviour.     

A10LaCdSb9 (A=Ca,Yb): A Highly Complex Zintl System and the Thermoelectric Properties

Two new Zintl compounds A₁₀LaCdSb₉ (A=Ca, Yb), namely, Ca_9.81(1)La_0.97(1)Cd_1.23(1)Sb₉ and Yb_9.78(1)La_0.97(1)Cd_1.24(1)Sb₉, have been designed and synthesized by applying the Zintl concept. Although both compounds are isoelectronic with their Ca₁₁InSb₉ and Yb₁₁InSb₉ analogues, they crystallize in a new structure type with the orthorhombic space group Ibam (No.72) and feature very complex anion structures, which are composed of unique [Cd₂Sb₆]^12? clusters, dumbbell‐shaped [Sb₂]^4? dimers, and isolated [Sb]^3? anions. For Yb_9.78(1)La_0.97(1)Cd_1.24(1)Sb₉, an extremely low lattice thermal conductivity of 0.29 W m^?1 K^?1 was observed at 875 K, which almost approaches the lowest reported limit of nonglassy or nonionically conducting bulk materials. According to thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, both compounds show very good thermal stability and no melting or phase transition processes were found below 1173 K. Although related thermoelectric property studies on Yb_9.78(1)La_0.97(1)Cd_1.24(1)Sb₉ only present a maximum ZT of 0.11 at 920 K, owing to its low Seebeck coefficients, these materials are still very promising for their high temperature stability and low thermal conductivity. Furthermore, as mixed cations exist with different charges, it makes this system very flexible in tuning the related electrical properties.     

Temperature dependence of121Sb nuclear quadrupole resonance frequencies in the spectra of M2Sb2SO4F6 (M = K,Rb, NH4)

The temperature dependence of the frequencies of¹²¹Sb nuclear quadrupole resonance in the spectra of M₂Sb₂SO₄F₆ (M = K, Rb, NH₄) was studied in the temperature range from 77 to 340 K. A secondary phase transition was found above 320 K for (NH₄)₂SO₄F₆.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1831–1833, October, 1994.This study was sponsored by the Russian Foundation for Basic Research (Grant No. 93-03-4394).     

Das erste Titanat mit „Stuffed Pyrgoms”︁: RbNa3Li12[TiO4]4 = RbNa3Li8{Li[TiO4]}4

The First Titanate with ?Stuffed Pyrgoms”?: RbNa₃Li₁₂[TiO₄]₄ = RbNa₃Li₈{Li[TiO₄]}₄ By heating a well grounded mixture of the binary oxides Rb₂O, Na₂O, Li₂O, and TiO₂ [Rb:Na:Li:Ti = 1.1:3.1:12.5:4.0; 780°C, 41 d] we obtained RbNa₃Li₈{Li[TiO₄]}₄ as colourless platelike crystals. This first titanate with ?stuffed pyrgoms”? is isostructural with RbNa₃Li₈{Li[SiO₄]}₄, CsKNa₂Li₈{Li[SiO₄]}₄ and CsKNaLi₉{Li[SiO₄]}₄ [2]. The compound crystallizes tetragonal I4/m with a = 1 125.8(1) pm and c = 652.4(1) pm (Guinier-Simon-Data, Z = 2). The structure was determined by four-cyrcle-data (Siemens AED2, MoK) and leds to the residual values R = 3.7% and R_w = 3.1% (additional data see text). The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN), Mean Fictive Ionic Raddii (MEFIR) and the Charge Distribution in Solids (CHARDI) are calculated and discussed.     

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.     

Barium antimonide oxide,Ba3Sb2O

The antimonide oxide Ba₃Sb₂O consists of discrete [Sb₂]^4? and O^2? anions, and crystallizes with a new structure type. The Sb—Sb distances are comparable to those known from electron‐precise zintl phases and the tetrahedral coordination of the O^2? anion is also observed in some other Ba‐rich metallide oxides.     

Nb28Ni33.5Sb12.5, a New Representative of the X-phase

The first ternary compound in the Nb–Ni–Sb system, Nb₂₈Ni_33.5Sb_12.5, has been synthesized and its structure has been determined by single-crystal X-ray diffraction methods. Nb₂₈Ni_33.5(2)Sb_12.5(2) adopts the X-phase structure type (orthorhombic, space group Pnnm, Z=1, a=13.2334(5) Å, b=16.5065(7) Å, c=5.0337(2) Å), which belongs to the set of tetrahedrally close-packed (TCP) structures adopted by many intermetallic compounds. Typical of such TCP structures, the atoms reside in sites of high coordination number, with Ni and Sb in CN12 and Nb in CN14, -15, and -16 sites. The relative importance of various metal–metal bonding interactions is discussed on the basis of extended Hückel band structure calculations. Nb₂₈Ni_33.5Sb_12.5 displays metallic behavior with a room-temperature resistivity of 2.3×10⁻⁴ Ω cm.     

Crystal chemistry of Co-doped Zn7Sb2O12

Zn₇Sb₂O₁₂ forms a full range of Co-containing α solid solutions, Zn_7−xCo_xSb₂O₁₂, with an inverse-spinel structure at high temperature. At low temperatures for x<2, the solid solutions transform into the low temperature β-polymorph. For x=0, the β→α transition occurs at 1225±25 °C; the transition temperature decreases with increasing x. At high x and low temperatures, α solid solutions are formed but are non-stoichiometric; the (Zn+Co):Sb ratio is >7:2 and the compensation for the deficiency in Sb is attributed to the partial oxidation of Co²⁺ to Co³⁺. From Rietveld refinements using ND data, Co occupies both octahedral and tetrahedral sites at intermediate values of x, but an octahedral preference attributed to crystal field stabilisation, causes the lattice parameter plot to deviate negatively from the Vegard's law. Sub-solidus compatibility relations in the ternary system ZnO-Sb₂O₅-CoO have been determined at 1100 °C for the compositions containing ?50% Sb₂O₅.