PREPARATION AND CRYSTAL-STRUCTURES OF METALLIC CM-248, BK-249, AND CF-249

The oxides of the TPE may be reduced with thorium or lanthanum followed by distillation to prepare the rare actinoid metals Cm-248, Bk-249, and Cf-249 in masses of 0.7 to 1.0 mg as micron films on tantalum and silica. The metal yields in the reduction were correspondingly 99, 85, and 84%. Each of the metals has a double HCP lattice at room temperature, with the constants falling from Cm to Cf. The high-temperature form of metallic Cm has an FCC structure (a = 0.4933 nm). The oxidation has been examined. The thermal-expansion coefficients of Cm-248 and Bk have been measured at 93-300 K.