- Crystal Structures of Photochemically Prepared (Xe2F11)2(MF6) (M = Sn, Pb) and (XeF5)4(Sn5F24) Containing Six- and Seven-Coordinated Tin(IV)
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Single crystals of [Xe2F11]2[SnF6], [Xe2F11]2[PbF6], and [XeF5]4[Sn5F24] were grown from saturated aHF solutions upon crystallizations. The crystal structures of isotypic [Xe2F11]2[SnF6] and [Xe2F11]2[PbF6] consist of [Xe2F11]+ cations and [MF6]2– anions (M = Sn, Pb) that interact by means of fluorine bridge contacts. The single crystal structure determination of [XeF5]4[Sn5F24] reveals that it is built of two-dimensional ([Sn5F24]4–)∞ grids and [XeF5]+ cations located between them. The 2D grids have a wave-like conformation. The ([Sn5F24]4–)∞ layer contains, both, six- and seven-coordinated Sn(IV) interconnected by bridging fluorine atoms. The coordination of Sn(IV) by seven fluorine atoms is unprecedented. Attempts to synthesize and grow single crystals of the [XeF5][MF5] (M = Zr, Hf, Ni, Pd) compounds failed.
- Mazej, Zoran,Goreshnik, Evgeny
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- XeF4 as a ligand for a metal ion
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Noble molecule: [Mg(XeF2)(XeF4)](AsF 6)2 is the first coordination compound, in which XeF 2 XeF4 are simultaneously coordinated to the same metal center (see structure; purple Xe, green F,
- Tavcar, Gasper,Zemva, Boris
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- Largest perfluorometallate [Ti10F45]5- oligomer and polymeric ([Ti3F13]-)∞ and ([TiF5]-)∞ anions prepared as [XeF5]+ salts
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Reactions between XeF2, TiF4 and UV-irradiated elemental F2 in anhydrous HF yielded XeF5TiF5 (XeF6·TiF4), [XeF5]5[Ti10F45] (XeF6·2TiF4), and [XeF5][Ti3F13] (XeF6·3TiF4) upon crystallization. [XeF5]5[Ti10F45] crystallizes in two crystal modifications at low (α-phase, 150 K) and ambient (β-phase, 296 K) temperatures. The crystal structure determination of [XeF5]5[Ti10F45] reveals the largest known discrete decameric [Ti10F45]5- anion built from ten TiF6 octahedra, sharing vertices, in the shape of a double-star. [XeF5]+ cations are completely ordered in the α-phase, while one of three crystallographically unique [XeF5]+ cations is two-fold disordered in the β-phase. The anionic part of [XeF5][Ti3F13] is built from tetrameric Ti4F20 and octameric Ti8F36 units sharing vertices and alternatively linked into ([Ti3F13]-)∞ columns. The charge balance is maintained by [XeF5]+ cations which form secondary Xe?F contacts with fluorine atoms of ([Ti3F13]-)∞ groups. The main structural feature of XeF5TiF5 is an infinite chain of distorted TiF6 octahedra joined by cis vertices.
- Mazej, Zoran,Goreshnik, Evgeny A.
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p. 7320 - 7325
(2016/09/12)
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- XeOF3-, an example of an AX3YE2 valence shell electron pair repulsion arrangement; Syntheses and structural characterizations of [M][XeOF3] (M = Cs, N(CH3) 4)
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The XeOF3- anion has been synthesized as its Cs + and N(CH3)4+ salts and structurally characterized in the solid state by low-temperature Raman spectroscopy and quantum-chemical calculations. Vibrational frequency assignments for [Cs][XeOF3] and [N(CH3) 4][XeOF3] were aided by 18O enrichment. The calculated anion geometry is based on a square planar AX3YE 2 valence-shell electron-pair repulsion arrangement with the longest Xe-F bond trans to the oxygen atom. The F-Xe-F angle is bent away from the oxygen atom to accommodate the greater spatial requirement of the oxygen double bond domain. The experimental vibrational frequencies and trends in their isotopic shifts are reproduced by the calculated gas-phase frequencies at several levels of theory. The XeOF3- anion of the Cs + salt is fluorine-bridged in the solid state, whereas the anion of the N(CH3)4+ salt has been shown to best approximate the gas-phase anion. Although [Cs][XeOF3] and [N(CH 3)4][XeOF3] are shock-sensitive explosives, the decomposition pathways for the anions have been inferred from their decomposition products at 20°C. The latter consist of XeF2, [Cs][XeO2F3], and [N(CH3)4][F]. Enthalpies and Gibbs free energies of reaction obtained from Born-Fajans-Haber thermochemical cycles support the proposed decomposition pathways and show that both disproportionation to XeF2, [Cs][XeO2F3], and CsF and reduction to XeF2, CsF, and O2 are favorable for [Cs][XeOF3], while only reduction to XeF2 accompanied by [N(CH3)4][F] and O2 formation are favorable for [N(CH3)4][XeOF3]. In all cases, the decomposition pathways are dominated by the lattice enthalpies of the products.
- Brock, David S.,Mercier, Helene P. A.,Schrobilgen, Gary J.
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p. 10935 - 10943
(2010/09/16)
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- Infrared spectroscopic observation of the radical XeF3 generated in solid argon
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Xenon trifluoride radicals were generated by the solid-state chemical reaction of mobile fluorine atoms with XeF2 molecules isolated in a solid argon matrix. On the basis of spectroscopic and kinetic FTIR measurements and performed quantum chem
- Misochko, Eugenii Ya,Akimov, Alexander V.,Belov, Vasilii A.,Tyurin, Daniil A.
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p. 8723 - 8728
(2009/12/08)
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- Chemical and physical properties of some xenon compounds
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Useful preparative reactions for several xenon compounds can be systematized as acid-base chemistry. The hydrolysis of XeF4 and ammonolysis of XeF6 have been investigated. The melting point of XeO4 and the melting point an
- Huston, John L.
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p. 685 - 688
(2008/10/08)
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- Chemical Application of 99Tc NMR Spectroscopy: Preparation of Novel Tc(VII) Species and Their Characterization by Multinuclear NMR Spectroscopy
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The 99Tc NMR parameters of a number of Tc(VII) and one Tc(V) species have been determined.The anion TcO4- (Ξ = 22.508311 MHz in H2O) was chosen as the standard for 99Tc NMR spectroscopy.A 99Tc-17O coupling constant of 131.4 Hz was obtained from a 17O- and 18O-enriched sample of TcO4- whose 99Tc spectrum also showed an isotopic shift of 0.22 ppm/mass number arising from a statistical distribution of 16O/17O/18O isotopic isomers.Technetium-99 and proton NMR provided definitive proof for the existence of the stereochemically nonrigid TcH92- anion.Both TcO3F and the novel TcO3+ cation were synthesized and characterized by 99Tc, 17O, and 19F NMR spectroscopy.Preliminary results on two new technetium(VII) oxyfluorides tentatively identified as F2O2TcOTcO2F2 and TcO2F3 are also reported.The diamagnetic d2 anion, TcO2(CN)43-, represents the most deshielded 99Tc environment encountered in the present study.
- Franklin, Kenneth J.,Lock, Colin J. L.,Sayer, Brian G.,Schrobilgen, Gary J.
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p. 5303 - 5306
(2007/10/02)
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- The xenon-fluorine system
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Equilibrium constants have been obtained in the Xe-F2 system in the temperature range 250-500°. The data show that only three binary fluorides, XeF2, XeF4, and XeF6, are present. There is no evidence for the existence of XeF8 at 250° and up to 500 atm of F2. A preparation of pure XeF6 is described. A molecular weight determination, some infrared measurements, and vapor pressure data obtained with this sample are reported. Values for the thermodynamic properties of formation of XeF2, XeF4, and XeF6 are derived from the equilibrium constant data. The average value of the two missing vibrational modes of XeF4 is evaluated to be 246 ± 10 cm-1 from an analysis of the equilibrium constant and molecular data. Thermodynamic properties of XeF2 and XeF4 are calculated from molecular data. The value of S° for XeF4 at 25° is 75.6 cal mole-1 deg-1, in agreement with a value of 75.3 cal mole-1 deg-1 calculated from calorimetric data and the heat of sublimation. A number of molecular models for XeF6 are examined in terms of their consistency with the equilibrium constant data. A definite choice among the various models is not possible, but the analysis favors a low symmetry for XeF6. Values of S° for XeF6 at 25° are derived for each model and may be useful to help determine the symmetry of XeF6 when calorimetric data become available. The average bond energy of XeF2 is 31.0 kcal and that of XeF4 is 30.9 kcal. For XeF6 the average bond energy is 29.7 kcal, so that the average energy for forming the last two bonds in XeF6 is 27.3 kcal.
- Weinstock, Bernard,Weaver, E. Eugene,Knop, Charles P.
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p. 2189 - 2203
(2008/10/08)
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