The conclusion of this examination of cluster structures and energetics is how important a triple bond is for the features of weakinteraction. The interaction among the local quadrupoles of the triple bonds, either in HCCH or HCN, is significant. The sizable dipole of HCN relative to the zero dipole of acetylene has some effect on acetylene clusters to which it is attached,
but in certain ways, the effect is small orheld in check. Perhaps the most significant consequence of the dipole character of HCN is in giving energetic preference to substitution sites in pure acetylene clusters that are on the outer surfaces rather than interior sites.