Plutonium oxysulfides

Plutonium oxysulfides are inorganic compounds of plutonium, oxygen and sulfur, where sulfur exists as sulfide (S^2-) or polysulfide () ions and plutonium exists in the trivalent state or tetravalent state. They are mixed oxide-sulfides and include Pu₂O₂S, Pu₄O₄S₃, PuOS, and Pu₂O₂S₃.

Compounds

Pu₂O₂S

Diplutonium dioxide monosulfide (Pu₂O₂S) is formed by reacting plutonium(III) oxide and plutonium sesquisulfide at 1400 °C:

Or the decomposition of Pu₄O₄S₃ at 1100 °C.

It is isostructural with (has the same structure as) cerium(III) oxysulfide, having a hexagonal structure with lattice parameters a=3.929 and c=6.768 Å.

Pu₄O₄S₃

Tetraplutonium tetroxide trisulfide (Pu₄O₄S₃) is formed by the decomposition of PuOS at 600 °C. It is a mixed valence compound, containing a 1:1 ratio of plutonium in its +3 and +4 oxidation states. It has a complex pseudo-hexagonal structure, with lattice parameters a=4.06, b=6.72, c=3.87 Å, and β=118°.

PuOS

Plutonium monoxide monosulfide (PuOS) is formed by reacting sulfur with Pu₂O₂S at 500 °C (though this process also creates Pu₂O₂S₃), or by reacting plutonium monosulfide with oxygen:

It is unstable, dissociating to Pu₄O₄S₃ at 600 °C. It adopts the same structure as uranium oxysulfide, UOS, with which it forms a solid solution. Its structure is tetragonal, with lattice parameters a=3.80 and c=6.59 Å. It contains plutonium in its +4 oxidation state.

Pu₂O₂S₃

Diplutonium dioxide trisulfide (Pu₂O₂S₃) is the other product formed by reacting Pu₂O₂S with sulfur. It is a polysulfide (compound containing sulfur-sulfur bonds) with plutonium in its +4 oxidation state, and its formula can be written as . It has a tetragonal structure with lattice parameters a=3.95 and c=7.95 Å.

See also

• Neptunium sulfides
• Plutonium sulfides

References