hydride

Imagine hydrogen, the simplest element, joining up with another element. That gives you a hydride. In a broad sense, the word is used for compounds of hydrogen with another element. In a narrower chemical sense, it often refers to cases where hydrogen behaves like a negative ion (H⁻), especially with metals. Some hydrides are useful reagents in chemistry, such as lithium aluminum hydride, while others are studied for storing hydrogen in materials. Not all hydrides behave the same way: some are ionic, some are covalent, and some have metallic behavior.

The term "hydride" refers to a compound of hydrogen with another chemical element. That sounds simple, but the word is used in more than one way. In the broad sense, chemists use it for many kinds of hydrogen compounds. In a narrower sense, especially in discussions of ionic compounds, it refers to situations where hydrogen acts as a negative ion, written as H⁻.

This narrower use appears in ionic hydrides such as sodium hydride (NaH), a strong base widely used in organic chemistry. But hydrides are not limited to ionic compounds. There are also covalent hydrides, where hydrogen shares electrons with another element, and metallic or complex hydrides, which can have structures that allow them to hold hydrogen within a material.

Because of that, context matters when you see the word "hydride." In one setting, it may mean a reactive reagent such as lithium aluminum hydride (LiAlH₄), which chemists use to reduce many compounds. In another, it may refer to materials studied for hydrogen storage or to compounds important in industrial processes. The key idea is that hydrogen is bonded to another element, but the exact meaning depends on the type of bonding and the chemical context.