Neptunium(III) iodide is the iodide of neptunium with the chemical formula NpI3.

Neptunium(III) iodide can be produced by the reaction of neptunium dioxide and aluminium iodide:[3] Neptunium(III) iodide is a hygroscopic brown solid with a melting point of 767 °C.

It is orthorhombic (plutonium(III) bromide structure), space group Ccmm (No.

63), lattice parameters a = 430pm, b = 1403pm and c = 995pm.

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