Anhydrous salts are chemical compounds that do not contain water molecules in their structure. They are formed when hydrated salts lose their water content, often through heating. These salts are typically used in various industrial applications, including as drying agents and in chemical reactions where water must be excluded. Common examples of anhydrous salts include sodium sulfate and calcium chloride. Anhydrous salts can absorb moisture from the air, making them useful in controlling humidity. Their properties differ from their hydrated counterparts, which can affect their solubility and reactivity in different environments.