PREPARATION AND PROPERTIES OF THE ACTINIDE BOROHYDRIDES: Pa(BH4)4, Np(BH4)4, AND Pu(BH4)4

The actinide borohydrides, Pa(BH{sub 4}){sub 4}, Np(BH{sub 4}){sub 4}, and Pu(BH{sub 4}){sub 4} have been synthesized. Pa(BH{sub 4}){sub 4}, a solid at 20{sup o} is isostructural with U(BH{sub 4}){sub 4}. Np(BH{sub 4}){sub 4} and Pu(BH{sub 4}){sub 4} are volatile liquids at 20{sup o} but are isostructural at low temperatures and crystallize in a tetragonal crystal structure type. The metal atom distances indicate the solid is monomeric and similar to Zr(BH{sub 4}){sub 4}. Preliminary Raman spectra on solid Np(BH{sub 4}){sub 4} support this idea. Gas-phase infrared spectra indicate theNp and Pu atoms in these compounds are surrounded by four BH{sub 4}{sup -} groups in a tetrahedral array with each B coordinated via 3 hyrodgen bridge bonds to the metal atom