Ionic hydrides are compounds formed between metals and hydrogen, where hydrogen acts as an anion (H⁻). These hydrides typically consist of alkali metals, such as sodium or potassium, and alkaline earth metals, like calcium or barium. They are characterized by their ionic bonding, which results in high melting and boiling points. These compounds are often solid at room temperature and can react with water to produce hydrogen gas and a corresponding metal hydroxide. Ionic hydrides are important in various applications, including hydrogen storage and as reducing agents in chemical reactions.