Polonium subjects were chosen because experimenters wanted persons who had not been exposed to polonium either through work or accident. All subjects had incurable diseases. Excretion of polonium was followed, and an autopsy was conducted at that time on the deceased patient to determine which organs absorbed the polonium. Patients' ages ranged from 'early thirties' to 'early forties'. The experiments were described in Chapter 3 of Biological Studies with Polonium, Radium, and Plutonium, National Nuclear Energy Series, Volume VI-3, McGraw-Hill, New York, 1950. Not specified is the isotope under study, but at the time polonium-210 was the most readily available polonium
Polonium dioxide cubic form is pale yellow, while the tetragonal form is red. Polonium dioxide darkens upon heating, and is chocolate brown at its sublimation point, 885 °C. The ionic radius of the ion is 1.02 or 1.04 Å; thus, the ratio of the ionic radii / is about 0.73, the lower limit of stability for the cubic crystal system, allowing polonium dioxide to have two modifications. When freshly prepared, polonium dioxide is always in the tetragonal form, and changes to the cubic form after being left to stand or after being cooled strongly. Polonium dioxide does not occur naturally due to