Vìsnik Odesʹkogo Nacìonalʹnogo Unìversitetu: Hìmìâ (Sep 2020)

AMPHOTERICITY OF OXIDE COMPOUNDS AS A CRITERION AND THE BASIS FOR THE CREATION OF FILM-FORMING MATERIALS

  • V. F. Zinchenko,
  • V. V. Menchuk

DOI
https://doi.org/10.18524/2304-0947.2020.3(75).211721
Journal volume & issue
Vol. 25, no. 3(75)
pp. 43 – 55

Abstract

Read online

The question of the quantitative determination of the amphotericity of oxides by the values of their electronegativity is considered. The approximate boundaries of the electronegativity of amphoteric oxides from 1.6 to 2.2 eВ1/2/О2- are established according to the concept of aciditybasicity of Lux-Flood. The possibility of the manifestation of amphoteric properties with a different ratio of acid and basic functions for oxides of the composition MO, M2O3, MO2, M2O5 and MO3is analyzed, and the oxides of the composition M2O3, exhibit the most balanced ratio. The limit values of electronegativity for acid and basic functions are established, which differ by 0.3-0.4 eВ1/2/О2-. The influence of the binary oxide form (oxo-, ortho-, meta-, etc.) on the value of the electronegativity of simple oxides, which they manifest during acid-base interaction, is explained. The influence of the acid-base interaction on the electronegativity of binary oxides at the formation of ternary oxides (complex sulfates, silicates and phosphates) of metals with their equalization and the acquisition of amphoteric properties is shown. The relationship between the electronegativity of simple oxides and their thermal characteristics (melting and boiling points) characterizing the strength of crystal lattices is established. It has been shown that amphoteric oxides having a predominantly covalent crystalline structure have higher thermal parameters than oxides of a predominantly ionic or molecular nature, i.e., basic or acidic oxides. On the other hand, having the most stable crystalline structure, they are less able to chemically interact with environmental components, that is, they have higher climatic stability compared to acidic or basic oxides. This indicates the possible ways of choosing simple oxides as the basis of film-forming materials, as well as creating binary and ternary oxides with the acquisition of amphoteric properties.

Keywords