Search

An equation correlating a parameter that described the enthalpy of nonspecific solvation of nonelectrolytes with a quantity characterizing intermolecular solute-solvent interaction was found. A simple and versatile method based on this equation was suggested for calculating the enthalpy of nonspecific solvation and the enthalpy of specific solute-solvent interaction.

The applicability of the approach based on the linear solvation energy relationship to describing the enthalpies of specific solvent-solute interactions was examined. In associated solvents, this approach reflects the contribution of specific interaction incorrectly. Although the enthalpies of solvation as a whole are described well, this is an “occasional” result and is due to averaging over different compounds and redistribu- tion of contributions from other types of interactions. A modification of this approach was suggested to take into account the effect of reorganization of an associated solvent.

Applicability of a linear solvation-energy approach for descripition of the solvation enthalpies of nonelectrolytes is examined. In most cases a good fit of experimental solvation enthalpies can be attained. However, the resulting data are difficult to interpret in terms of different types of intermolecular interactions.

The structure of [Co(NH3)5NO2]C2O4 is solved and refined (space group Immm, a=7.428(2), b=9.790(3), c=6.568(1) A, V=477.6(2) A3, Z=2; R1=0.0177, wR2=0.0279 for F2>4σ(F2); R1=0.1177, wR2=0.0643 for all data; residual electron density from 0.125 to −0.140 e/A3). Specific contacts in the structure are analyzed. Crystal chemical interpretation is suggested to explain the occurrence of photodecomposition rather than photochemical bond isomerization under the action of light in cobalt(III) nitropentammoniate oxalate crystals, in contrast to all previously investigated cobalt(III) nitropentammoniates.

The crystal structure of potassium peroxodisulfate was determined. The crystals are triclinic, a =5.115(1),b =7.034(2), c =5.505(1) a, α =106.32(2),gb =90.18(2), γ =106.12(2)‡, Vcell = 181.90(7) a3, space group PĪ, Z =1, dcalc =2.468 g/cm3 [“Syntex P21,” λCuKα, 994 reflections measured in a whole sphere to 2Τmax =114‡, including 496 independent reflections (Rint = 0.0571), R(F) = 0.0391, wR(F2) = 0.0933 for 486 Fhkl > 4Σ(F)]. An absorption correction (Μ = 171.37 cm−1) was applied taking into account the shape and size of the crystal using data about face indices. The representative of the single crystal was proven by comparing the experimental and calculated diffractograms. The geometrical characteristics of S2O82: S-O 1.645(2), S = 0 1.421(3)-1.429(2), O-O 1.495(5) a, S-O-O 106.2(2)‡.

A computerzed system was developed and integrated into a thermally polished glass line to control the temperature parameters in its annealing lehr. This served to optimize the annealing of Metelitsa glass, to cut down to 2 h the time required for the lehr to attain steady-state operation, and to raise the glass yield to 0.75. Suitable prompts were devised for operators in charge of the annealing operation, and the optimal format was found for the presentation of information about the on-going process.