Calculated from the atomic weight and the atomic volume. The unit cell, containing 16 atoms, has a volume of 319.96 cubic Å, according to Siegfried S. Hecker (2000). »Plutonium and its alloys: from atoms to microstructure«(PDF). Los Alamos Science. 26: 331.. This gives a density for 239Pu of (1,66053906660×10−24g/dalton×239,0521634 daltons/atom×16 atoms/unit cell)/(319,96 Å3/unit cell × 10−24cc/Å3) ali 19,85 g/cc.
