Diamond formation from C-60 fullerene under high pressures

An X-ray phase analysis of C-60 fullerene polyhydrogenized in a hydrogen at mosphere at 100-120 degrees C and compressed at 900 degrees C under a press ure of 7 GPa was carried out. After heating under pressure, the polyhydroge nized C-60 fullerene decomposes into diamond and graphite, the phase ratio being independent of the duration of exposure to pressure (from 15 to 60 mi n). The fact that the diamond phase begins to form under milder conditions is explained by the preliminary exposure of the C-60 fullerene to a hydroge n atmosphere.