Synthesis and Structure of Ag4Te(SO4) – a New Compound Featuring a Silver‐Telluride Framework

Tetrasilver telluride sulfate was obtained as a black air‐stable polycrystalline powder; its structure was determined from X‐ray powder diffraction data. The new compound crystallizes in the cubic space group P2₁3, with the unit cell parameter a = 8.6263(2) Å and Z = 4. The crystal structure of Ag₄Te(SO₄) is composed of a positively charged silver‐telluride three‐dimensional framework, in which the isolated tetrahedral SO₄^2– anions are embedded. The framework features an irregular coordination for tellurium atoms with a coordination number of six and manifold Ag–Ag contacts ranging from 2.99 to 3.14 Å. The distortion of the SO₄^2– anion as well as the interactions within the framework and between the framework and the SO₄^2– anions are analyzed with the help of the structural data, vibrational spectra, and band structure calculations.     

Cs2Ba(O3)4 · 2 NH3, das erste ionische Erdalkaliozonid

Cs₂Ba(O₃)₄ · 2 NH₃, the First Ionic Alkaline Earth Metal Ozonide Cs₂Ba(O₃)₄ · 2 NH₃ is the first ionic ozonide containing an alkaline earth metal cation. Its synthesis has been achieved via partial cation exchange of CsO₃ dissolved in liquid ammonia. According to a single crystal X‐ray structure determination (Pnnm; a = 6.312(2) Å, b = 12.975(3) Å, c = 8.045(2) Å; Z = 2; R₁ = 4.6%; 848 independent reflections) ozonide anions, cesium cations and ammonia molecules form a CsCl‐type arrangement, where Cs⁺ and NH₃ occupy one half of the cation sites, each. Ba²⁺ is coordinated by four ozonide groups and two ammonia molecules. Because of a short hydrogen bond to one of the terminal oxygen atoms, the respective O–O‐distance in the ozonide ion is longer than the other. The shortest intermolecular O–O‐distance ever observed in ionic ozonides has been found in this compound, which can be taken as a first clue for the radical ozonide anion to dimerize like the isoelectronic SO₂^– does.     

Synthesis and Characterization of the Trisulfate Pb[S3O10] and Theoretical Analysis of H2S3O10

The reaction of (NH₄)₂PbCl₆ and fuming sulfuric acid (65 % SO₃) in a sealed glass tube at 250 °C led to colorless single crystals of Pb[S₃O₁₀] (orthorhombic, Pbcn, Z = 4, a = 10.9908(4), b = 8.5549(3), c = 8.0130(3) Å, V = 753.42(5) ų). The compound shows a three‐dimensional linkage of the tenfold oxygen coordinated Pb²⁺ ions and exhibits the unusual trisulfate anion, [S₃O₁₀]^2–, that consists of three vertex connected [SO₄] tetrahedra. The distances S–O within the S–O–S bridges of the anion are remarkable asymmetric with distances of 155 and 169 pm, respectively. This structural feature is well reproduced by calculations on a PBE0/cc‐pVTZ and a MP2/cc‐pVTZ level of theory. Similar calculations allow also for an inspection of the yet unknown corresponding acid, H₂S₃O₁₀. Also for this acid non‐symmetric S–O–S bridges are predicted. The thermal behavior of Pb[S₃O₁₀] is characterized by the loss of two equivalents of SO₃ at low temperature and the decomposition of intermediate Pb[SO₄] at higher temperature.     

Solid polymer electrolytes. IV. Preparation and characterization of novel crosslinked epoxy‐siloxane polymer complexes as polymer electrolytes

Two series of novel crosslinked siloxane‐based polymers and their complexes with lithium perchlorate (LiClO₄) were prepared and characterized by Fourier transform infrared spectroscopy, solid‐state NMR (¹³C, ²⁹Si, and ⁷Li nuclei), and differential scanning calorimetry. Their thermal stability and ionic conductivity of these complexes were also investigated by thermogravimetric and AC impedance measurements. In these polymer networks, poly(propylene oxide) chains with different molecular weights were introduced through self‐synthesized epoxy‐siloxane precursors cured with two curing agents. The glass‐transition temperature (T_g) of these copolymers is dependent on the length of the ether units. The dissolution of LiClO₄ considerably increases the T_g of the polyether segments. The dependence of the ionic conductivity was investigated as a function of temperature, LiClO₄ concentration, and the molecular weight of the polyether segments. The ion‐transport behavior was affected by the combination of the ionic mobility and number of carrier ions. The ⁷Li solid‐state NMR line shapes of these polymer complexes suggest a significant interaction between Li⁺ ions and the polymer matrix, and temperature‐ and LiClO₄ concentration‐dependent chemical shifts are correlated with ionic conductivity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1226–1235, 2002     

Site Preference of Cations and Structural Variation in MgAl2–xGaxO4 (0 ≤ x ≤ 2) Spinel Solid Solution

The crystal structures of MgAl_2–xGa_xO₄ (0 ≤ x ≤ 2) spinel solid solutions (x = 0.00, 0.38, 0.76, 0.96, 1.52, 2.00) were refined using ²⁷Al MAS NMR measurements and single crystal X‐ray diffraction technique. Site preferences of cations were investigated. The inversion parameter (i) of MgAl₂O₄ (i = 0.206) is slightly larger than given in previous studies. It is considered that the difference of inversion parameter is caused by not only the difference of heat treatment time but also some influence of melting with a flux. The distribution of Ga³⁺ is little affected by a change of the temperature from 1473 K to 973 K. The degree of order‐disorder of Mg²⁺ or Al³⁺ between the fourfold‐ and sixfold‐coordinated sites is almost constant against Ga³⁺ content (x) in the solid solution. A compositional variable of the Ga/(Mg + Ga) ratio in the sixfold‐coordinated site has a constant value through the whole compositional range: the ratio is not influenced by the occupancy of Al³⁺. The occupancy of Al³⁺ is independent of the occupancy of Ga³⁺, though it depends on the occupancy of Mg²⁺ according to thermal history. The local bond lengths were estimated from the refined data of solid solutions. The local bond length between specific cation and oxygen corresponds with that expected from the effective ionic radii except local Al–O bond length in the fourfold‐coordinated site and local Mg–O bond length in the sixfold‐coordinated site. The local Al–O bond length in the fourfold‐coordinated site (1.92 Å) is about 0.15 Å longer than the expected bond length. This difference is induced by a difference in site symmetry of the fourfold‐coordinated site. The nature that Al³⁺ in spinel structure occupies mainly the sixfold‐coordinated site arises from the character of Al³⁺ itself. The local Mg–O bond length in the sixfold‐coordinated site (2.03 Å) is about 0.07 Å shorter than the expected one. Difference Fourier synthesis for MgGa₂O₄ shows a residual electron density peak of about 0.17 e/ų in height on the center of (Ga_0.59 Mg_0.41)–O bond. This peak indicates the covalent bonding nature of Ga–O bond on the sixfold‐coordinated site in the spinel structure.     

Voltammetric Determination of BHT Antioxidant at Gold Electrode in Biodiesel

The voltammetric determination of synthetic antioxidant 2,6‐di‐tert‐butyl‐4‐methylphenole (BHT) was studied using linear‐sweep voltammetry (LSV) and cyclic voltammetry (CV) with a gold electrode and performed in isopropanol media containing either 0.1 mol L^?1 H₂SO₄ or 0.1 mol L^?1 LiClO₄ as supporting electrolyte. The results obtained have revealed that the most reliable detection was acquired in acidic media (isopropanol–H₂SO₄) whereas the use of isopropanol? LiClO₄ solution exhibited poorer reproducibility due to possible passivation of the electrode. Real samples of biodiesel mixture were analyzed without any special sample treatment or separation and results were compared with those obtained by FTIR‐spectroscopy.     

Vibrational Spectroscopic Study of 2-Methoxyethyl Ether Complexed with Lithium and Sodium Trifluoromethanesulfonate

A comparative vibrational spectroscopic study of 2-methoxyethyl ether solutions containing dissolved LiCF₃SO₃ and NaCF₃SO₃ is reported. The strong, infrared active metal oxygen stretching mode was observed as a broad band at 400 cm^-1 in the LiCF₃SO₃ solution and at 180 cm^-1 in the NaCF₃SO₃ solution. Several low-frequency modes originating in intramolecular CF₃SO₃^- motions are reported and assigned. The relative concentrations of the various ionic species present are described as a function of salt concentration in both systems. Finally, changes in the local conformation of the 2-methoxyethyl ether backbone due to interactions of the ether oxygens with the cations are discussed.     

A helical coordination polymer of zinc(II), 4‐hydroxybenzohydrazide and sulfate ions

In the structure of the novel zinc complex catena‐poly[[diaqua(4‐hydroxybenzohydrazide)zinc(II)]‐μ‐sulfato], [Zn(SO₄)(C₇H₈N₂O₂)(H₂O)₂]_n, the complex cations are linked by sulfate counter‐ions into helical polymeric chains extending along the b axis. Each helix is stabilized by six intrachain hydrogen bonds involving stronger O—H...O (1.83–2.06 Å) and weaker N—H...O (2.20–2.49 Å) interactions. The Zn^II atom displays a distorted octahedral geometry formed by the 4‐hydroxybenzohydrazide ligand, two water molecules and two SO₄²⁻ ions, which is very similar to the metal‐atom environment in a previously reported Co^II complex [Zasłona, Drożdżewski & Kubiak (2010). J. Mol. Struct. 982 , 1–8], especially the Zn—O and Zn—N bond lengths of 2.0453 (12)–2.1602 (9) and 2.1118 (12) Å, respectively.     

3Mg(OH)2·MgSO4·8H2O: A Metastable Phase in the System Mg(OH)2‐MgSO4‐H2O

In the course of investigations relating to magnesia oxysulfate cement the basic magnesium salt hydrate 3Mg(OH)₂ · MgSO₄ · 8H₂O (3–1–8 phase) was found as a metastable phase in the system Mg(OH)₂‐MgSO₄‐H₂O at room temperature (the 5–1–2 phase is the stable phase) and was characterized by thermal analysis, Raman spectroscopy, and X‐ray powder diffraction. The complex crystal structure of the 3–1–8 phase was determined from high resolution laboratory X‐ray powder diffraction data [space group C2/c, Z = 4, a = 7.8956(1) Å, b = 9.8302(2) Å, c = 20.1769(2) Å, β = 96.2147(16)°, and V = 1556.84(4) ų]. In the crystal structure of the 3–1–8 phase, parallel double chains of edge‐linked distorted Mg(OH₂)₂(OH)₄ octahedra run along [–110] and [110] direction forming a pattern of crossed rods. Isolated SO₄ tetrahedra and interstitial water molecules separate the stacks of parallel double chains.     

NO(HSO4), a Fairly Ionic Solid

The colourless solid NO(HSO₄), known as “lead‐chamber crystals”, was investigated ever since its first preparation more than two centuries ago. Its overall ionic nature now is confirmed by X‐ray crystallography [Pna2₁, a = 7.3558(4), b = 6.8924(3), c = 7.7017(3) Å, Z = 4]. The next neighbours of the NO⁺ cations are four hydrogensulfate oxygen atoms, forming a distorted square at a distance of about 2.5 Å from the nitrogen atom. The square pattern next to the nitrogen atom is the most widespread coordination figure about an NO⁺ ion in a nitrosyl salt. Depending on the anion, the interaction goes along with a decrease of the N–O stretch's excitation energy.     

Reversible SO2 Uptake by Tetraalkylammonium Halides: Energetics and Structural Aspects of Adduct Formation Between SO2 and Halide Ions

Contact with SO₂ causes almost immediate dissolution of tetraalkylammonium halides, R₄NX, (R = CH₃ (Me), X = I; R = C₂H₅ (Et), X = Cl, Br, I; R = C₄H₉ (nBu), X = Cl, Br), with the formation of an adduct, [R₄N]⁺[(SO₂)_nX]^– (n = 1–4). Vapor pressure measurements indicate the proclivity for SO₂ uptake follows the order N(CH₃)₄⁺ < N(C₂H₅)₄⁺ < N(C₄H₉)₄⁺. This trend is in accord with the Jenkins–Passmore volume‐based thermodynamic model. Born–Haber cycles, incorporating the lattice energy and gas phase energy terms, are used to evaluate the energetic feasibility of reactions. Density functional theory calculations (B3PW91; 6‐311+G(3df)) have been used to calculate the energetics of (SO₂)_nX^– (X = Cl and Br) anions in the gas phase. The experimental studies show that tetraalkylammonium halides are feasible sorbents for SO₂. In order to correlate the theoretical model, experimental enthalpy, Δ_rH° and entropy, Δ_rS° changes have been determined by the van't Hoff method for the binding of one SO₂ molecule to (C₂H₅)₄NCl, resulting in the liquid adduct (C₂H₅)₄NCl · SO₂. The structure of the analogous 1:1 bromide adduct, (C₂H₅)₄NBr · SO₂, has been determined by single‐crystal X‐ray diffraction (monoclinic, P2₁/c, a = 9.1409(14) Å, b = 12.3790(19) Å, c = 11.3851(17) Å, β = 107.952(2)°, V = 1225.6(3) ų). The structure consists of discrete alkylammonium cations, bromide anions and SO₂ molecules with short contacts between the anion and SO₂ molecules. The (C₂H₅)₄N⁺ cationadopts a transoid conformation with D_2d symmetry, and represents a rare example of a well‐ordered (C₂H₅)₄N⁺ cation in a crystal structure. The Br^– anions and SO₂ molecules forms a chain, (SO₂Br^–)_n, with bifurcated contacts. Non‐bonding electron pairs on the halide anions engage in electrostatic interactions with the sulfur atoms and charge‐transfer interactions with the antibonding S–O orbitals of the bound SO₂ moiety. Raman and ¹⁷O NMR spectra provide compelling evidence for a charge‐transfer interaction between SO₂ molecules and the halide ions.     

Silver(I) sulfate coordination polymers with 4,4′‐bipyridazine and pyridazino[4,5‐d]pyridazine

Poly[[μ₄‐4,4′‐bipyridazine‐μ₅‐sulfato‐disilver(I)] monohydrate], {[Ag₂(SO₄)(C₈H₆N₄)]·H₂O}_n, (I), and poly[[aqua‐μ₄‐pyridazino[4,5‐d]pyridazine‐μ₃‐sulfato‐disilver(I)] monohydrate], {[Ag₂(SO₄)(C₆H₄N₄)(H₂O)]·H₂O}_n, (II), possess three‐ and two‐dimensional polymeric structures, respectively, supported by N‐tetradentate coordination of the organic ligands [Ag—N = 2.208 (3)–2.384 (3) Å] and O‐pentadentate coordination of the sulfate anions [Ag—O = 2.284 (3)–2.700 (2) Å]. Compound (I) is the first structurally examined complex of the new ligand 4,4′‐bipyridazine; it is based upon unprecedented centrosymmetric silver–pyridazine tetramers with tetrahedral AgN₂O₂ and trigonal–bipyramidal AgN₂O₃ coordination of two independent Ag^I ions. Compound (II) adopts a typical dimeric silver–pyridazine motif incorporating two kinds of square‐pyramidal AgN₂O₃ Ag^I ions. The structure exhibits short anion–π interactions involving noncoordinated sulfate O atoms [O...π = 3.041 (3) Å].     

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.     

π‐Complexes of Copper(I) with Terminal Alkynes. Synthesis and Crystal Structure of [(HC≡CCH2NH3)(Cu2Br3)] π‐Complex

Crystals of the zwitterionic copper(I) π‐complex [(HC≡CCH₂NH₃)Cu₂Br₃] have been synthesized by interaction of CuBr with [HC≡CCH₂NH₃]Br in aqueous solution (pH < 1) and X‐ray studied. The crystals are monoclinic: space group P2₁/n, a = 6.722(4), b = 12.818(8), c = 9.907(3) Å, β = 100.25(4)°, V = 840.0(8) ų, Z = 4, R = 0.0592 for 3015 reflections. The crystal structure of the π‐complex contains isolated [(HC≡CCH₂NH₃)⁺(Cu₂Br₃)^?]₂ units which are incorporated into a framework by strong hydrogen N–H···Br and C≡C–H···Br bonds. The length of π‐coordinated propargylammonium C≡C bond is equal 1.216(8) Å and Cu(I)–(C≡C) distance equals 1.958(5) Å.     

Synthesis,Spectroscopic, and X‐Ray Diffraction Studies of cis‐Dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl3 H‐pyrazol‐3‐onato) Tin(IV)

Reaction between an aqueous ethanol solution of tin(II) chloride and that of 4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐one in the presence of O₂ gave the compound cis‐dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐onato) tin(IV) [(C₂₆H₂₆N₄O₄)SnCl₂]. The compound has a six‐coordinated Sn^IV centre in a distorted octahedral configuration with two chloro ligands in cis position. The tin atom is also at a pseudo two‐fold axis of inversion for both the ligand anions and the two cis‐chloro ligands. The orange compound crystallizes in the triclinic space group P 1 with unit cell dimensions, a = 8.741(3) Å, b = 12.325(7) Å, c = 13.922(7) Å; α = 71.59(4), β = 79.39(3), γ = 75.18(4); Z = 2 and D_x = 1.575 g cm^–3. The important bond distances in the chelate ring are Sn–O [2.041 to 2.103 Å], Sn–Cl [2.347 to 2.351 Å], C–O [1.261 to 1.289 Å] and C–C [1.401 Å] the bond angles are O–Sn–O 82.6 to 87.7° and Cl–Sn–Cl 97.59°. The UV, IR, ¹H NMR and ¹¹⁹Sn Mössbauer spectral data of the compound are reported and discussed.     

Electrochemical Performance of PEO10LiX-Li2TiO3 Composite Polymer Electrolytes

Introduction Recently, polymer electrolytes have attracted much attention for their potential use in replacing flammable organic solvent electrolytes currently used in lith-ium-ion batteries, thus improving the safety of re-chargeable lithium batteries. Moreover, the batteries with PE can be made in any shape, which make fully use of the space of electronic devices. PEO is a linear polymer with helix structure, and its structure makes it have much higher dissolution ability for salt even tho…     

Structural Variability of R2C Adducts of 3a,6a‐Diaza‐1,4‐diphosphapentalene: Tuning the N→P Bonding

3a,6a‐Diaza‐1,4‐diphosphapentalene (DDP) reacts with hexachlorocyclopentadiene to form a stable adduct (ClC)₄C=DDP ( 4 ). The phosphorus atom involved into coordination has a pyramidal arrangement but retains partial double bonding with carbon [1.752(3) Å]. At the same time, the P–N bond remains covalent [1.824(3) Å]. The adduct 4 is better described as a zwitterionic compound with strongly delocalized positive and negative charges. A similar zwitterionic adduct DDP=C(CN)₂ was prepared by the reactions of dichloro‐DDP ( 7 ) with malononitrile in the presence of Et₃N. DFT calculations showed that related structures are formed in the case of the substituents (ClC)₄C=, (HC)₄C=, (NC)₂C=, and (MeCO)₂C=, possessing electron‐delocalizing properties. Compounds with other R₂C groups (R = Ph, Me, C₆F₅, Cl), possessing electronegative properties as well, but insufficient e‐delocalization, demonstrate the noncovalent P–N bonding and a little shorter R₂C–P bond lengths (ca. 1.70 Å).     

Synthesis and Crystal Structure of (PCl4)[Re2Cl9]

The reaction between PCl₃ and ReCl₅ yielded at 200 °C the ionic tetrachlorophosphonium dirhenium nonachloride, (PCl₄)[Re₂Cl₉]. Single crystal X-ray diffraction analysis revealed a monoclinic unit cell: a = 8.616(3) Å, b = 10.449(4) Å, c = 9.397(3) Å, β = 99.72(3)°, V = 833.9(5) ų, Z = 2, sp. gr. P2₁/m, wR₂ = 0.1083 and R₁ = 0.0527. The ionic compound is built from tetrahedra PCl₄⁺ and face-sharing bioctahedra Re₂Cl₉^–. The Re–Re distance, 2.724 Å, indicates the presence of direct Re-Re interaction.     

Structural Investigations and Thermal Behaviour of Mercury(II) Sulfito Complexes

The crystal structures of (NH₄)[HgSO₃Cl] ( 1 ) and of (NH₄)₂[Hg(SO₃)₂] ( 2 ) were determined from single crystal diffractometer data sets. 1 : 22 °C, Pnma, Z = 4, a = 15.430(3), b = 5.525(1), c = 6.679(1) Å, R(F) = 0.0256, R_w(F²) = 0.0642 (all 1056 unique reflections). 2 : ?108 °C, P2₁2₁2₁, Z = 4, a = 6.2240(4), b = 9.3908(6), c = 13.6110(8) Å, R(F) = 0.0179, R_w(F²) = 0.0493 (all 2699 unique reflections). The structure of 1 contains bent Cl‐Hg‐SO₃ entities (site symmetry m; d(Hg‐Cl) = 2.3403(13) Å, d(Hg‐S) = 2.3636(12) Å, ∠(Cl‐Hg‐S) = 164.51(5)°, d(S‐O) 2×1.458(3) Å, 1.468(4) Å, = 1.461Å) linked to undulated ribbons parallel to the b ‐axis by intermolecular secondary bonds SO···Hg (d(O···Hg) = 2×2.595(3) Å). These ribbons in turn aggregate to layers around the bc ‐plane. The layers are stacked along the a ‐axis with interlayer distances of a /2. The structure of 2 is made up of O₃S‐Hg‐SO₃ moieties (d(Hg‐S) = 2.3935(7), 2.3935(8) Å; ∠(Hg‐S‐Hg) = 174.41(3)°; = 1.474Å), that are linked to ribbons parallel to the a axis by coordination of Hg to three remote O atoms (2.801(4) < d(Hg‐O) < 2.844(3) Å). Adjacent ribbons are joined together by an additional Hg‐O contact of 2.733(3) Å, leading to a three‐dimensional anionic framework. Both crystal structures are stabilised by disordered NH₄⁺ cations, placed between the anionic layers or in the vacancies of the framework, via moderate hydrogen bonding interactions N‐H···O with donor‐acceptor distances ranging from 2.8 to 3.2Å. 1 and 2 were further characterised by thermal analysis (TG, DSC). They start to decompose at temperatures above 130 °C.     

Apparent molar volumes of aqueous sodium trifluoromethanesulfonate and trifluoromethanesulfonic acid from 283 K to 600 K and pressures up to 20 MPa

Relative densities of NaCF₃SO₃(aq) at molalities 0.073 ≤ m/(mol-kg^-1) ≤ 1.68 were measured with vibrating-tube densimeters from 283 K to 600 K and from 0.1 MPa to 20 MPa. Relative densities of HCF₃SO₃(aq) at molalities 0.12 < m/(mol-kg^-1) < 2.1 were determined at temperatures from 283 K to 328 K at 0.1 MPa. Apparent molar volumes calculated from the measured densities were represented by the Pitzer ion-interaction treatment. The temperature and pressure dependence of the standard partial molar volume and the second virial coefficients in the Pitzer equation were expressed by empirical expressions in which the compression coefficient of water and temperature were used as independent variables. The conventional standard partial molar volumes V‡(CF₃SO ₃ ^- , aq) fromT = 283 K to 573 K were calculated from the experimental values for V‡(NaCF₃SO₃, aq) and known values for V‡(Na⁺, aq). The values of V‡(CF₃SO_3/-, aq) at temperatures from 283 K to 328 K obtained from the values of V‡(NaCF₃SO₃, aq) and V‡(HCF₃SO₃, aq) agree to within 1.2 cm³-mol^-1.