Plutonium tetrachloride complexes

For the larger chloride ion, the final member in the series is the tetrachloride, An02CLi A The uranium, neptunium, and plutonium tetrachloride dianions have been isolated with a number of different cations, for example, Na+, NH4+, K+, Cs+, K+18-crown-6, and so on. The An=0 distances were found to be 1.768, 1.751, and 1.737A for An = U, Np, and Pu, respectively. The An-Cl distances in these complexes is virtually unchanged 2.675 A (U), 2.659 A (Np), and 2.656 A (Pu). These stmctural data suggest that the chloride hgands are bound in essentially a purely ionic manner while the covalent nature of the An=0 bond is preserved. 

Tetrachloride and tetrabromide complexes are known for thorium, protactinium, uranium, neptunium, and plutonium. These are similarly produced by halide-based oxidation of metals or hydrides, or by halogenation of oxides. A common structural type is reported for most compounds. The reported structure of thorium tetrachloride reveals that the coordination geometry about the metal is dodecahedral.The compounds are generally volatile and can be sublimed. The gas-phase electron diffraction structure of suggests that the molecule is... 

The corresponding chloride and bromide are made by heating the dioxide with carbon tetrachloride and aluminium bromide respectively. The only tetrahalide of plutonium yet isolated is the fluoride, PUF4, although the tetrachloride appears to exist in solution. Americium forms a tetrafluoride and also a complex fluoride, KAmFg. 

Attempts to make the octamethylplutonocene derivative by addition of tetramethyl[8]annulene dianion to the tetrachloride resulted in the reduction of Pu(IV) by the tetramethyl[8]annulene dianion to Pu(III).i When the borohydride complexes of neptunium and plutonium are used in place of the halide salts acceptable yields of the bis(tetra-roethyl[8]annulene) complexes were obtained.21... 

The reaction of actinide tetrachlorides (thorium through plutonium) with the potassium salt of cyclo-octatetraene (COT) results in the formation of actocene complexes, rf — CgH8)2An, named by analogy with ferrocene. All these compounds have a sandwich structure in which two planar COT rings enclose a metal atom. 

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