Plutonium(IV) sulfate
Chemical compound
From Wikipedia, the free encyclopedia
Plutonium(IV) sulfate is an inorganic salt consisting of plutonium and sulfate ions, with the chemical formula Pu(SO4)2·xH2O. It has been observed as a tetrahydrate, where x=4,[1][2] as well as an anhydrous form, where x=0.[4] The tetrahydrate has been used as a primary standard for plutonium.[5]
| Names | |
|---|---|
| IUPAC name
Plutonium(IV) sulfate | |
| Identifiers | |
3D model (JSmol) |
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| Properties | |
| Pu(SO4)2 | |
| Molar mass | 506.18 g/mol |
| Appearance | Red crystalline solid[1] |
| Somewhat soluble[2] | |
| Structure | |
| Orthorhombic | |
| Fddd (α-Pu(SO4)2·4H2O)[1][3] Pnma (β-Pu(SO4)2·4H2O)[3] | |
| mmm (α-Pu(SO4)2·4H2O)[1] | |
| Related compounds | |
Other anions |
Plutonium(IV) oxide Plutonium(IV) fluoride |
Other cations |
Uranium(IV) sulfate Uranyl sulfate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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In aqueous solution
Reactions
At high temperatures, plutonium(IV) sulfate tetrahydrate decomposes. It first releases its water between 85 °C and 535 °C to eventually form anhydrous plutonium(IV) sulfate. Anhydrous plutonium(IV) sulfate decomposes between 605 °C and 810 °C to produce plutonium(IV) oxide.[4] During decomposition of plutonium(IV) sulfate, it releases hazardous sulfur oxides.[2] At normal temperatures, however, plutonium(IV) sulfate tetrahydrate is stable in air, even at high humidity.[5][7]
Structure
In plutonium(IV) sulfate tetrahydrate, the sulfate and water ligands are monodentate, with bonds between the plutonium atoms and the oxygen atoms in water and sulfate. Each plutonium atom has a coordination number of 8, and a coordination geometry of square antiprismatic. Plutonium(IV) sulfate tetrahydrate crystals have an orthorhombic crystal structure. Hydrogen bonds exist between hydrogen atoms in the water molecules and oxygen atoms in the sulfate ions that are not attached to the plutonium atom.[1][3]
Polymorphs
Plutonium(IV) sulfate tetrahydrate has two polymorphs– α-Pu(SO4)2·4H2O and β-Pu(SO4)2·4H2O. The two forms share the same molecular geometry, but differ in the functional nature of the hydrogen bonds. The α-form transitions into the β-form at ~120°C.[3]
α-Pu(SO4)2·4H2O has a unit cell with dimensions a=26.53Å, b=12.00Å, and c=5.69Å, where there are 8 formula units per unit cell.[3]
β-Pu(SO4)2·4H2O has a unit cell with dimensions a=14.54Å, b=10.98Å, and c=5.67Å, where there are 4 formula units per unit cell.[3]
Hazards
Plutonium(IV) sulfate is a highly dangerous compound, due to it being radioactive and carcinogenic.[2]