Based on a unified model of chemical bonding that combines its three extreme types (covalent, metallic, and ionic) in the form of mixed homo- and heteronuclear classes, for the first time within the system of chemical bonds and compounds (SCBC) in the form of a ‘chemical triangle,’ the boundary of their ‘degeneration’ has been determined, beyond which they cease to exist. Within this model, the ‘degeneration’ of a chemical bond occurs through the gradual transformation of an extremely covalent localised chemical bond into bonds mixed with its metallic or ionic varieties. As a result, there is a tendency for the number of elements in a chemical compound to increase, its mass to increase, and the energy of the chemical bond between them to decrease, until it is eliminated. The ratios of the components of homo- and heteronuclear chemical bonds between two elements based on 111 atoms of D.I. Mendeleev's periodic table, which totalled 6,216 units. As a result, within the area of the ‘chemical triangle’ with the limiting (100%) values of the covalent, metallic and ionic components, the boundary of the ‘inner triangle’ was determined, occupying the upper left part of its total area, beyond which no chemical bonds are formed. The vertices C, M and I of this ‘inner triangle’, connected by three sides, or boundaries, beyond which the ‘degeneration’ of chemical bonds occurs, are characterised by the following values of the bond components: the upper vertex C (degree of covalency, CC, = 100% and degree of metallicity, CM, = 0%), the lower left vertex M (CC = 18.037% and CM = 81.963%) and the lower right vertex I (CC = 31.921%, CM = 22.166% and degree of ionity, CI = 45.913%).
CHEMICAL BOND, COVALENCE, METALLICITY, IONICITY, UNIFIED MODEL OF CHEMICAL BONDING, SYSTEM OF CHEMICAL BONDS AND COMPOUNDS, ‘CHEMICAL TRIANGLE’, ‘DEGENERATION’ OF CHEMICAL BONDING