<span>Salt compounds are composed of ions that form a tightly packed and ordered network, which is called a crystal lattice. It is held together by electrostatic forces known as ionic bonding. Ionic bonding refers to the chemical bond between two oppositely charged ions - a cation and an anion. This type of bond forms when there is a large electronegativity difference between two atoms. </span>
Roman numerals are used in naming ionic compounds when the metal cation forms more than one ion. The metals that form more than one ion are the transition metals, although not all of them do this.
