The crystal structure of beta plutonium metal

Abstract

β-Pu is monoclinic body-centered with 34 atoms per unit cell. At 190 °Ca=9.284, b=10.463, c=7.859Å, β=92.13 °and the density is 17.70 g.cm-3.The space group is I2/m. One set of two plutonium atoms are in centers of symmetry. Three sets of four plutonium atoms are in reflection planes, one set of four on twofold axes and two sets of eight in general positions. The thirteen parameters in the structure have been determined to an accuracy of about 0.04Å.The seven different kinds of plutonium atoms in the structure have coordination number of twelve, thirteen or fourteen. The mean atomic radius is 1.60Å for coordination number twelve.