Volumetric properties of disodium dihydrogen pyrophosphate aqueous solution from 283.15 to 363.15 K at 101.325 kPa.

The purpose of this exploration was to determine the density and volumetric properties of the aqueous solution of Na2H2P2O7 with the molality varied from 0.08706 to 0.88402 mol·kg-1 measured at temperature intervals of 5 K from 283.15 to 363.15 K at 101.325 kPa using Anton Paar Digital vibrating-tube densimeter. The thermal expansion coefficient (α), apparent molar volume (VΦ), expansibility (ϕE), and partial molar volume (VB) of Na2H2P2O7 (aq) against temperature and molality have been evaluated from density data. On the basis of Pitzer ion-interaction apparent molar volume theory, the Pitzer single-salt parameters (ßM,X0v, ßM,X1v, ßM,X2v and CM,Xv, MX = Na2H2P2O7), and their correlation coefficients ai of the temperature-dependence formula f (i, p, T) = a1 + a2ln(T/298.15) + a3(T - 298.15) + a4/(620 - T) + a5/(T - 227) for Na2H2P2O7 were obtained for the first time. It was revealed that predicted apparent molar volumes agreed well with the experimental values indicating the single salt parameters and the temperature-dependent formula are reliable.

Thermodynamic and Dynamic Modeling of the Boron Species in Aqueous Potassium Borate Solution.

The concentration of B(OH)3, B(OH)4 -, B3O3(OH)4 -, and B4O5(OH)4 2- in the solution and the solubilities in the system KCl-K2SO4-K2B4O7-H2O and its subsystems were calculated on the basis of the Pitzer model. The mole fraction of the four boron species is mainly affected by m(B) in the solution but less by m(Cl-) and m(SO4 2-). m(Cl-) and m(SO4 2-) mainly affect the solubility of K2B4O5(OH)4·2H2O. The calculated solubilities in the system KCl-K2B4O7-H2O agree well with the experimental data. The results show that the standard chemical potentials of K2B4O5(OH)4·2H2O at 298.15 K obtained in this work is reliable. The transformation between the boron species at 298.15 K was also conducted with the density functional theory (DFT) method. The results affirm that the boron species can transform other boron species as the boron concentration in the solution changes.

Triimidazolium tris-(pyridine-2,6-di-carboxyl-ato)dysprosate(III) trihydrate.

The structure of the title compound, (C(3)N(2)H(5))(3)[Dy(C(7)H(3)NO(4))(3)]·3H(2)O, contains a mononuclear Dy(III) complex with the rare earth metal cation in a distorted tricapped trigonal-prismatic environment. The Dy(III) ion is in each case O,N,O'-chelated by three tridentate pyridine-2,6-dicarboxyl-ate anions. Three protonated imidazole mol-ecules act as counter-cations and three lattice water mol-ecules are also present. Numerous N-H⋯O and O-H⋯O hydrogen bonding inter-actions, some of which are bifurcated, help to stabilize the packing of the structure.