Neptunium tetrachloride

Neptunium tetrachloride is a binary inorganic compound of neptunium metal and chlorine with the chemical formula NpCl4.

Synthesis
The compound can be prepared by:


 * the reaction of neptunium nitride with HCl:
 * 2 NpN + 8 HCl -> N2 + 4 H2 + 2 NpCl4


 * the reaction of neptunium sulfide with HCl:


 * Np2S3 + 8 HCl -> 2 NpCl4 + 3 H2S + H2


 * the reaction of carbon tetrachloride with neptunium(IV) oxide or NpO2. Neptunium tetrachloride is formed as a yellow sublimate.


 * NpO2 + CCl4 -> NpCl4 + CO2

Other reactions are also used.

Physical properties
NpCl4 crystallizes in tetragonal crystal system of space group I4/amd.

Chemical properties
The compound reacts with ammonia to produce neptunium trichloride:


 * 6 NpCl4 + 2 NH3 -> 6 NpCl3 + 6 HCl + N2

Neptunium tetrachloride can be reduced to neptunium trichloride by hydrogen at 450 °C.


 * 2 NpCl4 + H2 -> 2 NpCl3 + 2HCl