121,123Sb NQR investigation of chlorofluoroantimonates(III) M2SbCl3F2 (M = Rb. Cs,and NH4)

Antimony(m) chlorofluoride complexes M₂SbCl₃F₂ (M = Rb, Cs, or NH₄) were studied by the^121,123Sb NQR method. A temperature range (77–285 K) with anomalous change in the NQR parameters and a second-order phase transition at 250–280 K for (NH₄)₂SbCl₃F₂ were found.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 382–385, February, 1996     

Variations of the shape of123Sb NQR tines in phase transitions in K2SbF5

Variations of the shape of¹²³Sb NQR lines in phase transitions in a new ionic conductor, potassium pentafluoroantimonite(ui), in the temperature range from 77 to 430 K were studied. The transition from a paraelectric phase to a commensurate phase occurs via incommensurate and commensurate-modulated phases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2497–2500, October, 1996.     

Manifestation of electron-nuclear motions in the123Sb NQR spectra of pentafluoroantimonites

A dependence between the quadrupole coupling constants (e ² Qq _zz ) and the asymmetry parameters of the electric field gradient (η) for the antimony atoms in the complex [SbF₅]²⁻ anions of M₂SbF₅ pentafluoroantimonites (M=Na, K, Rb, Cs, NH₄, Ti, and Et₂NH₂) was revealed from the¹²³Sb NQR spectra at 77 K. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1988–1990, October, 1998.     

N nuclear quadrupole resonance of picolinic,nicotinic, isonicotinic and dinicotinic acids

The ¹⁴N nuclear quadrupole resonance (NQR) quadrupole coupling tensors of picolinic, nicotinic, isonicotinic and dinicotinic acids have been determined. Two different ¹⁴N quadrupole coupling constants 1007 kHz and 4159 kHz have been observed for picolinic acid demonstrating the presence of both protonated and non-protonated nitrogen atoms in this system in the solid. Only one set of non-protonated ¹⁴N NQR lines has been observed in other pyridinecarboxylic acids demonstrating the absence of the protonated zwitter ion forms observed in picolinic acid. The non-protonated ¹⁴N quadrupole coupling constant is the highest for the non-protonated nitrogen in picolinic acid and decreases to 3774 kHz in nicotinic acid and 3570 kHz in isonicotinic acid. It is the lowest in dinicotinic acid where the corresponding ¹⁴N quadrupole coupling constant is 2794 kHz. The observed anomalous decrease in the ¹⁴N quadrupole coupling constant of dinicotinic acid with decreasing temperature is tentatively explained as reflecting the increase in the residence time of the N–H?O bonded proton in the potential well close to the nitrogen.     

Ba2InSbO6双钙钛矿的水热合成及121Sb M(o)ssbauer谱表征

在温和水热条件下,合成了双钙钛矿型Ba2InSbO6,采用XRD、TEM、XPS、ICP及IR等技术表征产物的结构及组成.XRD数据的Rietveld拟合结果表明,Ba2InSbO6为a=0.416782(13)nm的立方钙钛矿结构,属于Pm-3m.121Sb M(o)ssbauer谱测试表明,产物的同质异能移可归属为SbV及Sb-O键具有明显的共价特征.合成条件的研究表明,Sb源对合成具有重要影响,且Sb2O3锑源可有效地降低杂质的生成.     

121Sb Mössbauer spectra of alkali metal antimonides M3Sb (M3 = Na3, K3, Na2K, Rb3)

¹²¹Sb Mössbauer spectra for M₃Sb (M₃ = Na₃, K₃, Na₂K, Rb₃) were measured at 12 K. The values of isomer shift (d) and quadrupole coupling constant suggest that the valence state of antimony in M₃Sb is –3. The d values increase in the order Rb₃Sb<K₃Sb<Na₃Sb<Na₂KSb. The differences in d values are discussed by examining M–Sb distances and bond valence for M–Sb interactions. Some covalent interactions between alkali metal atoms and antimony atom are suggested.     

Darstellung,Ramanspektren und Kristallstrukturen von V2O3(SO4)2, K[VO(SO4)2] und NH4[VO(SO4)2]

Preparation, Raman Spectra, and Crystal Structures of V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] The oxo-sulfato-vanadates(V) V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] have been prepared as crystals suitable for X-ray structure determination. In all structures sulfate acts as an unidentate ligand only toward a single vanadium atom. The structure of V₂O₃(SO₄)₂ consists of a threedimensional network of pairs of cornershared VO₆ octahedra with one terminal oxygen atom each, and SO₄ tetrahedra. All oxygen atoms of the sulfate ions are coordinated. NH₄[VO(SO₄)₂] and K[VO(SO₄)₂] are isostructural. VO₆ octahedra with one terminal oxygen atom and pairs of sulfate tetrahedra form infinite chains by corner sharing. The chains are weakly interlinked to layers. The sulfate ions are distorted towards planar SO₃ molecules and single oxygen atoms attached to vanadium. This structural detail gives an explanation for the mechanism of the reversible reaction K[VO(SO₄)₂] ? K[VO₂(SO₄)] + SO₃ at 400°C. Raman spectra of the compounds have been recorded and interpreted with respect to their structures. Crystal data: V₂O₃(SO₄)₂, monoclinic, space group P2₁/a, a = 947.2(4), b = 891.3(3), c? 989.1(4) pm, β = 104.56(3)°, Z = 4, 878 unique data, R(R_w) = 0.039(0,033); K[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(2), b = 869.6(9), c = 1 627(1)pm, Z = 4, 642 unique data, R(R_w) = 0,11(0,10); NH₄[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(1), b = 870.0(2), c = 1 676.7(4)pm, Z = 4, 768 unique data, R(R_w) = 0.088(0.083).     

121,123Sb NQR study of antimony(III) fluoride complexes

Antimony(III) complexes with nitrogen-containing ligands: 2SbF₃·Gly, SbF₃·Gly, SbF₃·2NA, SbFO·Gly, MSb₂F₇ (M=Et₂NH₂, Bu₄N, HNA⁺), MSbF₄ (M=Et₂NH₂, Pr₂NH₂, Bu₄N, HNA⁺, HGly⁺), M₂SbF₅ (M=Et₂NH₂ and Pr₂NH₂), where Gly is glycine (⁺NH₃CH₂COO⁻) and NA is nicotinamide (β-C₅H₄NCONH₂), were studied by^121,123Sb NQR spectroscopy at 77 K. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2232–2236, November, 1998.     

123Sb NQR and 19F NMR study of potassium,rubidium, and cesium heptafluorodiantimonates(iii)

The dynamics of crystal lattices of potassium, rubidium, and cesium heptafluorodiantimonates(iii) and specific features of internal rotations of the Sb₂F₇ fluoride groups in these compounds were studied using ¹²³Sb NQR in the temperature interval from 77 to 325 K and ¹⁹F NMR in the temperature interval from 240 to 470 K in combination with X-ray diffraction and thermogravimetric analyses. The distinctions in the dynamic behavior of the fluoride ions with changing the size (polarizability) of outer-sphere cations are discussed. The structural phase transition in CsSb₂F₇ was revealed at 425—430 K accompanied by the appearance of a high ion conductivity ( 1.3·10^–3 S cm^–1 at 450 K). A second type phase change can exist at 220—270 K.     

Temperature dependence of nqr spectra in MSbBrF3 (M=Na,Cs, NH4) and Cs3Sb2Br9

Conclusions We have studied the temperature dependence of the NQR parameters of¹²³Sb and⁸¹Br in the range 77–360 K for the complexes of MSbBrF₃ (M=Na, Cs, NH₄) and Cs₃Sb₂Br₉. We have established the temperature regions for which piezoelectric properties appear in the crystal hydrate NaSbBrF₃.H₂O, and in the compounds MSbBrF₃ (M=Na, NH₄) and Cs₃Sb₂Br₉ anomalous changes appear in the dependences of the quadrupole coupling constant, the asymmetry parameter of the electric field gradient for the antimony atoms and the resonance frequency of the bromine atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1501–1504, July, 1987.     

Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

The behavior of different anilines H₂NC₆H₄R (R = o-Me, p-Me, o-, m- and p? ⁱ Pr, p-OMe, p-CO₂Et) and 2,6-Me₂C₆H₃NH₂ towards trihalophosphoranes was studied. 2,6-Me₂C₆H₃NH₂ failed to form the diaminophosphonium salt [Ph₂PNH(2,6-Me₂C₆H₃)₂]Br, and the aminophosphine oxide Ph₂(2,6-Me₂C₆H₃NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.     

Tetrafluoroaurate(III) der Lanthaniden M2F[AuF4]5 (M = Tb,Dy, Ho,Er)

Tetrafluoroaurates(III) of Lanthanoides M₂F[AuF₄]₅ (M = Tb, Dy, Ho, Er) Tetrafluoroaurates(III) M₂F[AuF₄]₅ with M = Tb, Dy, Ho, Er, all yellow, have been obtained. From single crystal data they crystallize triclinic, space group P1 -C¹_i (No. 2) with Tb: a = 1 194,34(7) pm, b = 798,46(6) pm, c = 902,02(7) pm, α = 89,033(7)°, β = 88,990(6)°, γ = 89,006(7)°; Dy: a = 1 191,66(9) pm, b = 796,33(8) pm, c = 899,65(9) pm, α = 88,956(8)°, β = 89,056(8)°, γ = 88,972(8)°; Ho: a = 1 189,06(10) pm, b = 795,46(6) pm, c = 896,81(7) pm, α = 88,912(8)°, β = 89,101(7)°, γ = 88,873(8)°; Er: a = 1 185,20(40), b = 793,98(14), c = 893,83(20), α = 88,751(23)°, β = 89,187(26)°, γ = 88,884(9)°     

Internal Mobility, Structure, Phase Transitions, and Ionic Conductivity in Thallium Fluoroantimonates(III) TlSb4F13 and TlSb3F10

Internal mobility in TlSb₄F₁₃ (I) and TlSb₃F₁₀ (II) was studied by ¹⁹F NMR spectroscopy in the temperature range 210-450 K. Types of ionic motion in the fluoride subsystem were determined. Phase transitions resulting in modifications with high ionic (superionic) conductivity above 420 K were established for both compounds (385-425 K). Using impedance spectroscopy, we studied the electrophysical properties of I and II in the temperature range 290-425 K ( 1.1×10^-3 and 1.0× 10^-3 S/cm for I and II, respectively; T=425 K).     

Enthalpies of crystallization of equilibrium solid phases occurring in the system K2SO4-(NH4)2SO4-H2O at 298.15 K

The concentration dependences of the differential enthalpies of solution were measured along several crystallization paths in the above-mentioned system, and the enthalpies of crystallization of mixed crystals occurring as a stable solid phase in the system were calculated on this basis. The obtained results confirmed the existence of a region of breaking continuity in the equilibrium solid phases.

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Zusammenfassung Für die obengennanten Systeme wurden, mehrere Kristallisationsradien entlang, die Messungen der Konzentrationsabhängigkeiten durchgeführt, die es unter differentiellen Lösungsenthalpien gibt. Auf dieses Grundlage wurden die Kristallisationenthalpien von Mischkristallen, die als stabile feste Phase vorkommen, bestimmt.Die erreichten Ergebnisse bestätigen die Tatsache, daß ein unterbrochenes Gebiet in den gleichgewichten festen Phasen vorkommt.

     

Jahn‐Teller‐Ordnung in Mangan(III)‐fluoridsulfaten. II. Phasenübergang und Verzwillingung bei K2[MnF3(SO4)] und 1D Magnetismus in Verbindungen A2[MnF3(SO4)] (A = K,NH4, Rb,Cs)

Jahn‐Teller Ordering in Manganese(III) Fluoride Sulfates. II. Phase Transition and Twinning of K₂[MnF₃(SO₄)] and 1D Magnetism in Compounds A₂[MnF₃(SO₄)] (A = K, NH₄, Rb, Cs) According to single‐crystal X‐ray investigations, K₂[MnF₃(SO₄)] crystallizes at low temperature, like the isostructural Rb, NH₄, and Cs analogues in space group P2₁/c, Z = 4, e.g. at 100 K with a = 7.197, b = 10.704, c = 8.427Å, β = 91.84°. Below about 300 K, the crystals are found to be [001] axis twins. Using a new integration method for area detector records, nearly complete intensity data could be gained allowing for structure refinements of similar quality as for untwinned crystals (e.g. at 100 K: wR₂ = 0.050, R = 0.020 for all reflections). With rising temperature, the monoclinic angle approaches continuously 90°. For an ordering parameter Δβ = β?90° a 2^nd‐order phase transition is observed with an exponent λ = 0.17. At the transition temperature of 280 K resulting from the fit, the monoclinic structure changes – with delay – to orthorhombic with the minimum super‐group Pnca, a = 7.243, b = 10.763, c = 8.457Å, R = 0.024, as found in an early structure determination at room temperature by Edwards 1971. In the chain‐like [MnF₃(SO₄)]^2? anions, manganese(III) is octahedrally coordinated by two trans‐terminal and two trans‐bridging fluorine ligands as well as by the O atoms of two trans‐bridging sulfate ligands. At low temperature, the octahedral elongation by the Jahn‐Teller effect alternates between a F–Mn–F and an O–Mn–O axis (antiferrodistortive ordering). All bridges are asymmetric. From about 320 K on they become symmetric. Due to 2D dynamical Jahn‐Teller effect all octahedra appear compressed. All compounds A₂[MnF₃(SO₄)] show 1D antiferromagnetism. The antiferrodistortive Jahn‐Teller order at low temperatures and the small bridge angles explain the much lower magnetic exchange energies and their inverse relation to the bridge angles as compared with other fluoromanganate(III) chain compounds with the usual ferrodistortive ordering.     

Synthese und Charakterisierung von Tetrabromoferraten(III) AFeBr4 mit einwertigen Kationen A  Cs,Rb, Tl,NH4, K,Na, Li,Ag

Preparation and Characterization of Tetrabomoferrates(III) AFeBr₄ with Monovalent Cations A ? Cs, Rb, Tl, NH₄, K, Na, Li, Ag Tetrabromoferrates(III) AFeBr₄ of the monovalent cations A ? Cs, Rb, Tl, NH₄, Na, Ag, Li have been prepared in closed ampoules by reaction of the appropriate bromides with iron and an excessive amount of bromine. The dark red compounds were characterized by DTA, Raman spectroscopy and X-ray powder diffraction. Their crystal structures have been assigned to five structure types, containing FeBr₄ anions. The coordination number runs from 12 (Cs⁺, Rb⁺) over 10 (NH₄⁺) and 8 (K⁺), to 6 (Na⁺, Ag⁺, Li⁺). Lattice parameters for all compounds see “Inhaltsübersicht”. CsFeBr₄ and RbFeBr₄ crystallize orthorhombic in the BaSO₄-type, NH₄FeBr₄ monoclinic in the KAlBr₄-type, KFeBr₄ orthorhombic in the GaGaCl₄-type, NaFeBr₄ monoclinic in the NaGaBr₄-type, AgFeBr₄ and LiFeBr₄ monoclinic in the LiAlCl₄-type, while the structure of TlFeBr₄ is still unknown.     

Synthesis and physicochemical properties of new hafnium fluoro complexes (NH4)6MHf4F23 (M = K, Rb, Cs)

Ammonium-containing hafnium fluoro complexes (NH₄)₆MHf₄F₂₃ (M = K, Rb, Cs), which crystallize in orthorhombic symmetry, were synthesized and studied. Their unit cell parameters were determined. The IR absorption spectra of the synthesized complexes were studied in the region of 350?C4000 cm^?1.     

ChemInform Abstract: Spectroscopic and Structural Studies of Difluorophosphoryl Azide F2P(O)N3, Difluorophosphoryl Isocyanate F2P(O)NCO,and Difluorophosphoric Acid Anhydride,F2(O)POP(O)F2.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Anionische Antimon(III)-Fluorokomplexe mit protonierten Azakronenethern als Gegenionen. Strukturen und Mößbauerspektren von [H2cyclam]2[Sb4F16] · 2 H2O, [H4cyclam][Sb2F10] · 2 HF und [H4(tetramethyl)cyclam]2[Sb4F15][HF2][F]4 (cyclam = 1,4,7,11-Tetraazacyclotetradecan)

Anionic Antimony(III) Fluoro Complexes with protonated Azacrownethers as Counterions. Crystal Structures and Mößbauer Spectra of [H₂cyclam]₂[Sb₄F₁₆] · 2H₂O, [H₄cyclam][Sb₂F₁₀] · 2 HF, and [H₄(tetramethyl)cyclam]₂[Sb₄F₁₅][HF₂][F]₄ (cyclam = 1,4,7,11-Tetraazacyclotetradecane) The title compounds are formed by reaction of SbF₃ with the respective azacrownether. [H₂cyclam]₂[Sb₄F₁₆] · 2 H₂O contains tetrameric anions which weakly associate to chains. The [H₂cyclam]²⁺ ions possess an unusual conformation due to intramolecular hydrogen bonds. [H₄cyclam][Sb₂F₁₀] · 2HF contains the dimeric hitherto unknown [Sb₂F₁₀]^4? ion; two HF molecules are attached to it by hydrogen bonds. The structure of [H₄(tetramethyl)cyclam]₂[Sb₄F₁₅][HF₂][F]₄ is made up of the two dimensional polymeric [HSb₄F₁₇]^4? anion. The tetra-protonated tetramethylcyclam ions form host-guest complexes with fluoride ions.     

Monitoring of the insecticide trichlorfon by phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy

Trichlorfon is an organophosphorus insecticide, which is extensively being used for protection of fruit crops. Trichlorfon is a thermal labile compound, which cannot be easily determined by gas chromatography (GC) and has no suitable group for sensitive detection by high performance liquid chromatography (HPLC). In this study, a ³¹P nuclear magnetic resonance (³¹P NMR) has been described for monitoring of trichlorfon without any separation step. The quantitative works of ³¹P NMR spectroscopy has been performed in the presence of an internal standard (hexamethylphosphoramide). Limit of detection (LOD) for this method has been found to be 55 mg L⁻¹, without any sample preparation, and the linear working range was 150-5500 mg L⁻¹. Relative standard deviation (R.S.D.%) of the method for three replicates within and between days was obtained ≤9%. The average recovery efficiency was approximately 99-112%. This method was applied for monitoring trichlorfon in a commercial insecticide sample and tomato sample.