Neptunium borohydride

Best Fit Force Constants for Solid Neptunium Borohydride at 77K... 

The only examples of compounds of this type are the borohydrides, MIV(BH4)4 (MIV = Th-Pu) and MIV(MeBH3)4 (MIV = Th, U, Np). These compounds are conveniently prepared by reaction, for example, of the metal tetrafluoride with A1(BH4)3 in a sealed tube, followed by vacuum sublimation of the product.159 The neptunium and plutonium compounds are liquids at room temperature and are more volatile than the thorium, protactinium or uranium analogues. 

Synthesis and Characterization of Protactinium(IV), Neptunium(IV), and Plutonium (IV) Borohydrides... 

Purification of the desired product is accomplished by sublimation where only the unreacted A1(BHi+)3 and AnCBH ) are volatile. The large difference in volatilities of these compounds permit easy separation. ThCBHit) and PaCBHit) are obtained on a 0° cold finger by heating the solid reaction mixture to 120° and 55°, respectively. Uranium, neptunium, and plutonium borohydrides sublime at room temperature and are collected in a dry ice trap through which the A1(BHi+)3 passes into a liquid nitrogen trap. 

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... 

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