Crystal lattice energies of alkali metal halides

An empirical relation for crystal binding energy in terms of the valence level splitting of the anion and the radius of the cation has been proposed. The results are much closer to the experimental values and comparable with those obtained by different methods. The anomalously high binding energy of fluorides has been discussed.     

Ion solvation of aqueous solutions of alkali, alkaline earth, and transition metal halides

The published data on the density and velocity of ultrasound are used to determine the ion solvation parameters of sodium, magnesium, and cobalt chlorides. It is shown that the solvation of typical coordination compounds, such as cobalt chloride, is determined by the same underlying systems and interactions as that of electrolytes with ions of alkali and alkaline earth metals.     

A halogen-bonding-based heteroditopic receptor for alkali metal halides

A new heteroditopic receptor for alkali metal halides has been designed and synthesized. It is comprised of a well-established motif for cation binding and a motif for halogen-bonding-based anion recognition processes. The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported. Thanks to the cooperativity of metal coordination and the strong I-...I halogen bonding, the ion pair is fully separated. The boosting effect of the binding of the anion through halogen bonding on the coordination of the cation by the receptor has been proved also in solution by NMR experiments. The selectivity of the new heterotopic receptor toward different alkali metal halides has been tested by ESI mass experiments.     

Interatomic distances in molecules of gaseous alkali metal halides

Summary One of the possible methods of comparative calculation was used for calculating interatomic distancesd in gaseous alkali halides. The average deviation of the calculated values ofd from experimental values was 0.0012 A (for 15 substances).Translated from Zhurnal Strukturnoi Khimii, Vol. 1, No. 4, pp. 399–403, November–December, 1960     

Effect of the nature of organic solvents on their interaction with metal halides

The radioactive tracer technique was used for studying the extraction and predicting the best conditions of separation of arsenic halides by organic solvents of different nature. Sulphuric acid was found to enhance the extraction of arsenic halides. Extraction of AsI₃ increases in the order cyclohexane <CCL₄ toluene <o-xylene <CHCl₄ and is quantitative by benzene and nitrobenzene. For a given extraction increases in the order AsCl₃<AsBr₃< <AsI₃. Spectral measurements were made on some solvents; at maximum absorption there was a linearity between absorbance and AsI₃ concentration up to 2·10⁻⁴ M for o-xylene and to 2.5·10⁻⁴ M for nitrobenzene.     

Effect of the nature of organic solvents on their interaction with metal halides

Journal of Radioanalytical and Nuclear Chemistry - A systematic study has been carried out on the extraction of thallium halides with aromatic hydrocarbons, TBP and Amberlite LA2. Extraction has...     

Correlations between photosorption and photocatalytic activities of alkali metal halides

An analysis of the correlation suggests that the common stages in photosorption, photooxidation and photodecomposition of some simple molecules on alkali metal halides are connected with catalyst photoexcitation.

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The solubility and solvation of salts in mixed nonaqueous solvents. 1. Potassium halides in mixed aprotic solvents

The solubilities of potassium fluoride, chloride, and bromide in acetonitrile, N,N-dimethylformamide, and dimethylsulfoxide and in binary mixtures of these solvents were determined at 25°C. The standard molar Gibbs free energies of solution, _solnG°, in the neat solvents were related to the polarizabilities and basicities of the anions and the dipole moments and acidities of the solvents. The values of _solnG° in the mixtures were fitted by expressions from the quasi-lattice quasi-chemical theory. The mean number of each kind of solvent in the nearest environment of the ions was obtained from these results.     

Nature of the complexes formed by alkali metal halides with phosphine oxides

Reaction of alkali metal halides (MX) with methylenediphosphine oxides and various related compounds in nonaqueous solutions leads to the formation of complex compounds. The compositions, properties, and stabilities of these compounds, which have been studied in detail in acetonitrile, are determined by the nature of the cations and anions of the alkali metal halides. Formation of neutral complexes with the composition [MX · L] and cationic complexes with the composition [ML]⁺ has been established. The most characteristic representative of complexes of the first type is [NaI · L]; in the complexes studied, L=R₂P(O)CH₂P(O)R₂ (R=Bu, BuO, or Ph), Ph₂P(O)CH₂P(O) (OC₂H₅)CH₂P(O)Ph₂ and (p-OCH₃C₆H₄)₂P(O)CH₂P(O)(C₆H₄CF₃-p)₂. Compound [LiL]⁺ is characteristic of complexes of the second type; the compounds containing Ph₃P(O), Ph₂P(O)CH₂P(O)Ph₂, and Ph₂P(O)CH₂P(O)(OC₂H₅)CH₂P(O)Ph₂ as ligands have been studied. Stability constants of the complexes [NaI · L] and [LiL]⁺ have been determined by measuring the dependence of the electrical conductivity of solutions of the alkali metal halides in acetonitrile on the concentration of the ligands. The complex-forming power of phosphine oxides increases with increase in the number of P=O groups. Stabilities of the complexes [NaI · L] with ligands with identical structure decrease with increase in the electronegativity of the substituents on the phosphorus atoms.     

Thermodynamics of aqueous solutions of the alkali metal sulfates

The available thermodynamic properties for aqueous solutions of each of the alkali metal sulfates have been combined and analyzed within the framework of the ion interaction model at temperatures up to 225°C. It was necessary to set ₁ equal to 1.4kg^1/2-mol^–1/2 in order to obtain a satisfactory fit. The temperature dependence of the ion interaction parameters was given the functional form used by Rogers and Pitzer⁽¹⁾ in their study of Na₂SO₄(aq). With few exceptions, it was possible to reproduce the available thermodynamic data for aqueous solutions of the alkali metal to within the estimated experimental error. Thermodynamic results for Na₂SO₄(aq) appear to be adequate in this temperature range, but enthalpy and heat capacity data for the other alkali metal sulfate solutions are conspicuously lacking. Activity coefficients of these electrolytes decreased to less than 0.1 at moderate molalities at the higher temperatures, and their order changed with increasing temperature; two results which could be due to a combination of hydration and association effects.Research sponsored by the Division of Chemical Sciences, Office of Basic Energy Sciences of the U.S. Department of Energy under contract DE-AC05-840R21400 with the Martin Marietta Energy Systems, Inc.     

Paper chromatographic behaviour of alkali metal ions in phenol-containing solvents

Summary The chromatographic behaviour of all alkali metal ions in phenol saturated with 2M hydrochloric acid has been examined by centrifugal and ascending chromatography. Separation with centrifugal development is about one hundred times more rapid than that obtained by the ascending technique. The shortest separation time achieved in these studies, six minutes, shows that centrifugal chromatography promises to be a useful rapid technique for the separation of short-lived fracium isotopes from a mixture of other alkali metals and for the routine analysis of alkali metals. The different degree of solvation of the cations by phenol, depending upon ionic size, is considered to be mainly responsible for the observed selective distribution of the alkali metal ions on the chromatogram.     

Electric conductance of dispersions of metal oxides in solutions of weak acids in mixed dioxane-water solvents

The electric conductance of solutions of sulfuric, oxalic, benzoic, and salicylic acid (up to 0.02 M) in dioxane-water mixed solvents (90% and 93% dioxane by mass) has been studied in the presence and absence of TiO(2) and Al(2)O(3) (0.5-5% by mass). TiO(2) and Al(2)O(3) enhanced the conductance of solutions of organic acids in aqueous dioxane. The conductance is interpreted in terms of adsorption of acid in molecular form, dissolution of ceramic oxides in form of anionic complexes, and leaching of acidic impurities from ceramic oxides.