Hydride ion
Charge: 1- · Type: Anion · Molar mass: 1.008 g/mol
Made of: hydrogen
How it forms
Hydrogen normally loses its electron, but very electropositive metals such as sodium and calcium can force hydrogen to accept an electron instead, forming H-. This happens when the metals react directly with hydrogen gas at high temperature.
Naming note
H- is the hydride ion, named with the -ide suffix like other anions. Do not confuse it with the hydrogen ion (H+), which has the opposite charge.
Examples in compounds
Sodium hydride
Calcium hydride
Lithium aluminium hydride