INFLUENCE OF TYPES OF CHEMICAL BANDS ON THE STRUCTURE AND PHYSICAL-CHEMICAL PROPERTIES OF METALS AND SEMICONDUCTORS AFTER MELTING.

Conditions for thermodynamic stability of the structure of some metals and semiconductors have been identified. Based on experimental results, the conditions of thermodynamic stability are explained from the scientific point of view of modern ideas about the structure of liquids. It can be concluded that the type of chemical bond in liquid indium does not change with increasing temperature. That is, during a first-order phase transition, the crystal-liquid transition occurs without changing the type of chemical bond. This type of transition is characteristic of all metals. Experimental results for tellurium indicate the existence of several structures during its melting. With a gradual decrease in the maximum values of the temperature dependence of the ultrasound speed, the intensity of their structure changes decreases. At the same time, these structural changes end at certain temperatures. For silicon in the range –250K above the melting point of silicon, the temperature dependence of the speed of propagation of ultrasound with a frequency of 2 MHz was studied in detail. Analysis of the results obtained using the model theory of compressibility of two-structure cluster liquids shows that structural changes in liquid silicon continue in the studied temperature range.