title: Sodium silicide
text: # 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.
  
  