L. A. Myund

X-ray diffraction study of isomorphous crystal nonahydrates of aluminum, gallium, and scandium perchlorates

Crystal structures of isomorphous crystal nonahydrates of aluminum, gallium, and scandium perchlorates were determined by the X-ray crystal analysis at room temperature. The estimate of associates present in concentrated solutions was carried out by the method of X-ray diffraction in aqueous solutions of aluminum perchlorate.

Structure of aqueous solutions of group IIIA metals perchlorates by near infrared spectroscopy

The state of water in aqueous solutions of group IIIA metal perchlorates at 25°C was studied by the IR spectroscopy in the range of 5400–7500 cm−1. The optical density values of the solution measured at different wavelengths were combined in a matrix of experimental data of the uniform dimension. The matrices were chemometrically analyzed. A number, spectra, and concentration profiles of the spectral forms existing in the solution were determined. By the principal component method, the IR spectra of the studied systems are grouped into the mathematical clusters according to the nature of the cation-water interaction in the solution. The combined use of the infrared spectroscopy and chemometric analysis showed that the structural changes in the solution predicted by the generalized phenomenological model are due to the existence and interconversion of the spectral forms.

Near infrared spectral studies of aqueous solutions of metal perchlorates in groups I A, II A, II B, III A and III B of the Periodic Table

Chemometrics of NIR spectra of aqueous salt solutions M(ClO4) n , where Mn+: Li+, Na+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+, Cd2+, Al3+, Ga3+, In3+, Sc3+, Y3+, La3+ were used to establish the effect of the cation nature on the structure of aqueous electrolytes solutions. Principal component analysis showed that near infrared (NIR) spectra of the systems under study are grouped into clusters. It was found that the values of the eutectic concentrations of aqueous salt solutions and the polarising powers of cations correlate. The combined use of NIR spectroscopy, chemometrics of the spectral data and a generalised phenomenological model of the structure of aqueous electrolytes solutions is a new approach to studying of the structure of concentrated solutions.

Structure of aqueous electrolyte solutions estimated by near infrared spectroscopy and chemometric analysis of spectral data

The IR spectra of aqueous solutions of MClO4, MNO3, MCl (M = Li, Na), CsCl, and Na2SO4 were measured at frequencies of 5400–7500 cm−1 over a wide concentration range from 0.12 M up to saturation concentrations at 25°C. Chemometric analysis of the experimental data matrix was performed. Regularity was detected in distribution of the IR spectra of the studied aqueous solutions on the the plot of analysis scores by the principal component method depending on the nature of the anion-water interaction. The influence of the nature of the salt anion and cation on the water structure in aqueous electrolyte solutions was demonstrated. The existence and interconversion of the spectral forms of water with changing electrolyte concentration in solution were revealed.

Detection of hydrate forms of lithium and sodium perchlorates in aqueous solutions using near infrared spectroscopy

A new approach to the study of concentrated electrolyte water solutions is proposed. NIR spectra of aqueous solutions of LiClO4 and NaClO4 were studied. The pure spectra and concentration profiles of spectral forms in the solutions were found by deconvolution of an experimentally measured data matrix. The chemometric analysis and the generalised phenomenological model of the structure of aqueous electrolyte solutions were used to establish that the variation in spectra of LiClO4 solutions with concentration is due to antibatic changes in the fractions of water that is unbonded with ions and of water in the structure of the cybotactic group of lithium perchlorate trihydrate. Corresponding changes in NaClO4 solutions are also associated with interconversion of sodium perchlorate forms of di- and monohydrates. Hydrate forms of lithium and sodium perchlorates in aqueous solutions are described, and a cybotactic group in a saturated solution is found to be equivalent to a solid-phase structure fragment. A strategy for selecting the nature of a background electrolyte is recommended.

Solubility of aluminum, gallium, and indium perchlorates in water

Solubility polytherms of the system M(ClO4)3-H2O (M3+ = Al3+, Ga3+, In3+) were measured. Positions of singular points and vitrification ranges were determined. Values of eutectic concentrations were compared with earlier known data on the inversion concentrations measured by the viscometry method. Compositions of found crystalline hydrates were calculated from the solubility polytherms. The concept of the ability of the studied aqua cations to show properties of aqua acids, of the structure of solutions of posteutectic concentrations (structurally forced processes and microheterogeneity), of the electronic structure of M3+ cations, and of the localized hydrolysis phenomenon were used to understand the existence of the polyaqua compounds.

Structural microheterogeneites in strontium perchlorate solutions of posteutectic concentrations

Aqueous solutions of strontium perchlorate were studied in a wide range of concentrations at room temperature by X-ray diffraction, thermogravimetry, and calorimetry. The features of the solubility polytherm of strontium perchlorate, that distinguish it from those of other Group II metal perchlorates, were explained in terms of two coexisting interconverting crystal hydrates.

On the role of triethanolamine in the charnell synthesis of zeolites

Using NMR of elements present in solutions for the synthesis of zeolites, we have investigated the state of solution components. Specific interaction of sodium aluminate with triethanolamine in the starting solution has been found, which determines the results of synthesis of NaX zeolies in the system studied.

Solubility polytherms and eutectic concentrations of scandium, yttrium, and lanthanum perchlorate solutions

Freezing points of solutions M(ClO4)3-H2O (M = Sc, Y, La) of different concentrations were determined. The solubility polytherms of the perchlorate systems studied, as well as aluminum, gallium, and indium perchlorates were compared with the concentration dependences of different properties of the corresponding solutions. Viscometry and IR spectroscopy allowed the special points on these dependences to be correlated with eutectic concentrations. Structural changes in the systems studied as a function of solute concentration were described.

On Inhibition of Calcium Sulfate Crystallization with Phosphonic Complexes

IR spectra of propylene glycol solutions in water were measured in the region of the first overtone of water. The inhibition efficiency of calcium sulfate was determined as a function of the pH value and propylene glycol content of water. A concept is suggested for taking into account the water-complexone interaction in inhibition of calcium sulfate crystallization with phosphonic acids.