Ionic Hydrides
Simple hydrides
A simple hydride is when a metal reacts with hydrogen to produce a simple ionic hydride, such as NaH.
Complex hydrides
A complex hydride is when the hydride reacts with an electroc deficient atom, such as Aluminium to form a negatively charged ion. These are normally very reactive.
4LiH + AlCl3 –> LiAlH4 + 3LiCl3
Covalent Hydrides
These are the products of reaction between a non-metal and hydrogen.
Interstital Hydrides
Hydrogen is a very small molecule, and therefore these can fit in small places, such as transition metal lattices.