Sodium silicide
# Sodium silicide

Sodium silicide (NaSi, $Na_4Si_4)$ is a binary inorganic compound consisting of sodium and silicon. It is a solid black or grey crystalline material.

Sodium silicide reacts readily with water yielding gaseous hydrogen and aqueous sodium silicate in an exothermic reaction (~175 $kJ·mol^{−1}):$

    2 NaSi + 5 $H_2O$ → 5 $H_2$ + $Na_2Si_2O_5$

This is used in hydrogen technologies to generate hydrogen as a fuel. And is also used as high energy dense storage for hydrogen under low pressure.

