I. Introduction. Background. Focus of the review. Review procedure and results. The NEA-TDB data base system. Presentation of the selected data. II. Standards and Conventions. Symbols, terminology and nomenclature. Units and conversion factors. Standard and reference conditions. Fundamental physical constants. III. Selected Uranium Data. IV. Selected Auxiliary Data. V. Discussion of Data Selection. Elemental uranium. Aqua ions. Oxide, hydride and hydroxide species. VI. Discussion of Auxiliary Data Selection. Reference list. Authors list. Formula list. Discussion of selected references. Ionic strength corrections. Assigned uncertainties. The estimation of entropies.

Chemical thermodynamics of uranium

A2B′B″O6 perovskites: A review

The linear generalized equation described in this paper provides a further dimension to the prediction of lattice potential energies/enthalpies of ionic solids. First, it offers an alternative (and often more direct) approach to the well-established Kapustinskii equation (whose capabilities have also recently been extended by our recent provision of an extended set of thermochemical radii). Second, it makes possible the acquisition of lattice energy estimates for salts which, up until now, except for simple 1:1 salts, could not be considered because of lack of crystal structure data. We have generalized Bartlett's correlation for MX (1:1) salts, between the lattice enthalpy and the inverse cube root of the molecular (formula unit) volume, such as to render it applicable across an extended range of ionic salts for the estimation of lattice potential energies. When new salts are synthesized, acquisition of full crystal structure data is not always possible and powder data provides only minimal structural in...

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Relationships among Ionic Lattice Energies, Molecular (Formula Unit) Volumes, and Thermochemical Radii.

(1979). The Chemical Thermodynamics of Actinide Elements and Compounds. Nuclear Technology: Vol. 42, No. 1, pp. 114-115.

The Chemical Thermodynamics of Actinide Elements and Compounds

The crystal structures of magnesite, calcite, rhodochrosite, siderite, smithonite and dolomite were refined by standard single crystal X-ray methods using diffraction data up to sin,9/A = 1.0A -1. The C-O bond lengths are essentially the same. Attention is drawn to short 0 - 0 contacts (2.85A in both magnesite and smithonite) outside the coordination figures. The Me06 octahedra are always elongated parallel (00.1); the distortion is not a monotone function of the Me-O distance. The approximation of four point charges for the (C03Y- ion for calcite gives good agreement between observation and classical electrostatic calculation when charges of 1+ for carbon and 1 - for oxygen are used.

Crystal structure refinements of magnesite, calcite, rhodochrosite, siderite, smithonite, and dolomite, with discussion of some aspects of the stereochemistry of calcite type carbonates

A virtually unprecedented exponential burst of activity resulted following the publication, in 1998, of an article by Michael Freeman (Freemantle, M. Chemical & Engineering News, 1998, March 30, 32...

Ionic liquids--an overview.

S4(AsF6)2.AsF3 was prepared by the reaction of sulfur with arsenic pentafluroide in liquid AsF3 (quantitatively) and in anhydrous HF in the presence of trace amounts of bromine. A single-crystal X-ray structure of the compound has been determined: monoclinic, space group P2(1)/c, Z = 4, a = 7.886(1) A, b = 9.261(2) A, c = 19.191(3) A, beta = 92.82(1) degrees, V = 1399.9(4) A3, T = 293 K, R1 = 0.052 for 1563 reflections (I > 2 sigma (I) 1580 total and 235 parameters). We report a term-by-term calculation of the lattice potential energy of this salt and also use our generalized equation, which estimates lattice energies to assist in probing the homopolyatomic cation thermochemistry in the solid and the gaseous states. We find S4(AsF6)2.AsF3 to be more stable (delta fH degree [S4(AsF6)2.AsF3,c] approximately -4050 +/- 105 kJ/mol) than either the unsolvated S4(AsF6)2 (delta fH degree [S4(AsF6)2,c] approximately -3104 +/- 117 kJ/mol) by 144 kJ/mol or two moles of S2AsF6 (c) and AsF3 (1) by 362 kJ/mol. The greater stability of the S(4)2+ salt arises because of the greater lattice potential energy of the 1:2 solvated salt (1734 kJ/mol) relative to twice that of the 1:1 salt (2 x 541 = 1082 kJ/mol). The relative lattice stabilization enthalpies of M(4)2+ ions relative to two M2+ ions (i.e., in M4(AsF6)2 (c) with respect to two M2AsF6 (c) (M = S, Se, and Te)) are found to be 218, 289, and 365 kJ/mol, respectively. Evaluation of the thermodynamic data implies that appropriate presently available anions are unlikely to stabilize M2+ in the solid phase. A revised value for delta fH degree [Se4(AsF6)2,c] = -3182 +/- 106 kJ/mol is proposed based on estimates of the lattice energy of Se4(AsF6)2 (c) and a previously calculated gasphase dimerization energy of 2Se2+ to Se(4)2+.

Preparation, X-ray crystal structure determination, lattice potential energy, and energetics of formation of the salt S4(AsF6)2.AsF3 containing the lattice-stabilized tetrasulfur [2+] cation. Implications for the understanding of the stability of M(4)2+ and M2+ (M = S, Se, and Te) crystalline salts.

Lattice potential energies for calcite, aragonite and vaterite: Estimation of the charge distribution on the carbonate ion, the enthalpy of formation, ΔHf°(CO32−) (g) and the enthalpy of solvation, ΔHsolv°(CO32−) (g) of the gaseous CO32− ion

Harry Donald Brooke Jenkins

Papers

Ionic liquids--an overview.

Preparation, X-ray crystal structure determination, lattice potential energy, and energetics of formation of the salt S4(AsF6)2.AsF3 containing the lattice-stabilized tetrasulfur [2+] cation. Implications for the understanding of the stability of M(4)2+ and M2+ (M = S, Se, and Te) crystalline salts.

Lattice potential energies for calcite, aragonite and vaterite: Estimation of the charge distribution on the carbonate ion, the enthalpy of formation, ΔHf°(CO32−) (g) and the enthalpy of solvation, ΔHsolv°(CO32−) (g) of the gaseous CO32− ion

Truncation of Bertaut Madelung series for lattices involving extended charge distributions

Thermodynamics of actinide perovskite-type oxides I. Enthalpy of formation of Ba2MgUO6 and Ba2MgNpO6☆