Plutonium oxysulfides

Plutonium oxysulfides are inorganic compounds of plutonium, oxygen and sulfur, where sulfur exists as sulfide (S2-) or polysulfide (Sn2−) ions and plutonium exists in the trivalent state or tetravalent state. They are mixed oxide-sulfides and include Pu2O2S, Pu4O4S3, PuOS, and Pu2O2S3.[1]

Compounds

Pu2O2S

Diplutonium dioxide monosulfide (Pu2O2S) is formed by reacting plutonium(III) oxide and plutonium sesquisulfide at 1400 °C:[1]

2 Pu2O3 + Pu2S3 → 3 Pu2O2S

Or the decomposition of Pu4O4S3 at 1100 °C.[1]

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.[1]

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°.[1]

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:[1]

PuS + ½ O2 → PuOS

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.[1]

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 (Pu4+)2(O2−)2S2−(S2−2). It has a tetragonal structure with lattice parameters a=3.95 and c=7.95 Å.[1]

See also

References

  1. ^ a b c d e f g h Marcon, Jean-Pierre (15 Jan 1969). Contribution to the study of actinide sulfides (Thesis). Faculte des Sciences de l'Universite de Paris (France).
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