Table 1.

The amounts of cohesive energy (eV) for $C_{20-n}^{}{X}_n$ (n = 1, 2, and 3; X = B, N, and P).

	X = B	X = N	X = P
${\text{C}}_{19}\text{X}$	7.780	7.805	7.685
${\text{C}}_{18}{\text{X}}_2$-1	7.652	7.720	7.550
${\text{C}}_{18}{\text{X}}_2$-2	7.684	7.727	7.615
${\text{C}}_{17}{\text{X}}_3$-1	7.460	7.619	7.476
${\text{C}}_{17}{\text{X}}_3$-2	7.479	7.617