9.2.1 The essence and characteristics of covalent bond Chemical bonding: A chemical bonding is an interaction between atoms or molecules and allows the formation of polyatomic chemical compounds. The theory of chemical bonding consists of 1)The ionic bond theory, 2)The metallic bond theory 3)The covalent bond theory1)The ionic bond theory, 9.2.1 The essence and characteristics of covalent bond Chemical bonding: A chemical bonding is an interaction between atoms or molecules and allows the formation of polyatomic chemical compounds. The theory of chemical bonding consists of : 2) The metallic bond theory 3) The covalent bond theory