Plutonium oxysulfides are inorganic compounds of plutonium, oxygen and sulfur, where sulfur exists as sulfide (S2-) 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