Abstract: By analyzing the potential of an octahedral alkali cation, the varying of the potential of alkali cation, whose position is in three different directions of [111], [110] and [100] was calculated.
The results show that off-center sites in K₃C₆₀ crystal actually exist in these three directions. The deviations from the center are different to be 0.98A, 0.78A,
0.56A respectively in [111], [110] and [100] directions. The potential at off-center site in [111] direction is the lowest, --508.59meV. The existence of off-center sites owes
to the short range interaction of alkali, especially the interaction between alkali and C₆₀ anions. The most important is that the site corresponding to the lowest
potential point is not at the symmetric center. The reason of the different deviations in these three directions is the different densities of C₆₀ anion in the
corresponding crystal planes.

Key words: K₃C₆₀ crystal, off-center site, octahedral symmetry, Lennard--Jones potential, crystal plane