Salt hydrates are compounds formed when salt crystals incorporate water molecules into their structure. These water molecules are chemically bonded to the salt, creating a stable solid that often appears as a crystalline material. Common examples include copper(II) sulfate pentahydrate and sodium sulfate decahydrate, which contain five and ten water molecules, respectively. When salt hydrates are heated, they can lose their water content in a process called dehydration, resulting in a dry salt. This property is useful in various applications, such as in desiccants that absorb moisture from the air, helping to keep environments dry and prevent damage from humidity.