Salts are not actually molecules. Instead, they are ionic compounds. Unlike covalent compounds that form discrete molecules, salts exist as a crystal lattice structure composed of positively charged ions, called cations, and negatively charged ions, called anions. These ions are held together by strong electrostatic forces. The simplest example is sodium chloride, or table salt, with the formula NaCl, representing one sodium ion for every chloride ion in the crystal structure.
Salts form a crystal lattice structure where ions are arranged in a regular three-dimensional pattern. In this structure, each positively charged ion is surrounded by negatively charged ions, and vice versa. This alternating arrangement creates a stable structure held together by strong electrostatic forces. The smallest repeating unit in this lattice, representing the simplest ratio of ions, is called a formula unit. For sodium chloride, the formula unit is NaCl, representing one sodium ion for every chloride ion in the crystal structure.
There are many different types of salts, each with their own unique properties and uses. The most familiar is sodium chloride, or table salt, which consists of sodium and chloride ions. Potassium chloride is often used as a salt substitute for people on low-sodium diets. Calcium carbonate, found in limestone and chalk, is used in antacids and as a calcium supplement. Magnesium sulfate, commonly known as Epsom salt, is used in bath soaks and has agricultural applications. Sodium bicarbonate, or baking soda, is used in cooking and cleaning. Each of these salts has a different formula unit representing the ratio of cations to anions in its crystal structure.