Neptunium arsenide

Neptunium arsenide is a binary inorganic compound of neptunium and arsenic with the chemical formula NpAs.^[1] The compound forms crystals.

Synthesis

Heating stoichiometric amounts of pure substances:

${\displaystyle {\mathsf {Np+As\ {\xrightarrow {T,I_{2}}}\ NpAs}}}$

Physical properties

Neptunium arsenide forms crystals of several modifications:^[2][3]

• Cubic system, space group Fm3m, cell parameters a = 0.5835 nm, exists at temperatures below –131 °С.
• Tetragonal system, cell parameters a = 0.58312 nm, c = 0.58281 nm, exists in the temperature range –131 to –98 °С.
• Cubic system, space group Fm3m, cell parameters a = 0.58318 nm, exists at temperatures above –98 °C.

Neptunium arsenide becomes