The Study of Regularities of Changing Melting Enthalpy of Intermetallides of Magnesium–Lantanoids Systems Rich in Magnesium

Providing a reasonable forecast of the required properties of intermetallic compounds (hereinafter also referred as intermetallides or IM) is an important scientific and commercial problem, which may be solved by focusing scientific researches and permanent generation of knowledge in this field. To date, researches in chemistry and physics of IM have been developing empirically for a simple reason, due to the complexity of describing the relationship between the crystal structure and chemical bonds, and, therefore, between all the properties of IM. IM is mainly characterized by metal type of chemical bond, as well as specific metallic properties. At the same time, among IM, there are also salt-like compounds with ionic bond, i.e. valency compounds formed from elements of different chemical nature, being stoichiometric compounds. The examples of such compounds are compounds with intermediate bond type, i.e. ionmetal and covalently-metal, as well as covalent bond types (e.g., NaAu). In the series of compounds of Mg with elements of the IV subgroup, along with decreasing the difference in the electrochemical characteristics of the components, the change in the IM properties is observed, from those peculiar to ionic compounds (for example, Mg2Si, Mg2Ge) to the properties typical of metals (Mg2Pb), etc. Due to the fact that lanthanides form the largest group of elements of the periodic system occurring in nature, and Mg is a relatively active chemical element in terms of IM formation (for example, it forms three IM with cadmium - Mg3Cd, MgCd and MgCd3), its oxides in slag provide decreasing average silicon content and increasing the stability of the silicon content in iron, being an important process indicator in the course of physicochemical reactions occurring in a blast furnace (for example, in the process of iron production). The presence of Si impurity (along with O, Au, Ti, V, Zr) produces the greatest effect on efficiency of solar cells, etc. [1–3]. Based on the foregoing, it is very important to study the state function, i.e. enthalpy of magnesium-lanthanide systems, rich in magnesium, and, based on the results of computer simulation, taking into account molecular dynamics method and other similar studies [4–8], to model regularities of changes in melting enthalpy of IM of the mentioned systems. The issue of modeling the pattern of change in melting enthalpy of IM of magnesium-lanthanide (Mg-Ln) magnesium-rich systems is considered based on systematic analyzing melting enthalpy of IM of Mg-Ln magnesium-rich system, including Mg2Ln, Mg3Ln and equimolar compound MgLn, implemented using semi-empirical method developed by N.S. Poluektov.