Succinylcholine has a 10-atom distance between its N atoms, like decamethonium. Yet it has been reported that it takes two molecules, as with acetylcholine, to open one nicotinic ion channel. The conformational explanation for this is that each acetylcholine moiety of succinylcholine prefers the "gauche" (bent, cis) state. The attraction between the N and O atoms is greater than the onium head repulsion. In this most populated state, the N-N distance is shorter than the optimal distance of ten carbon atoms and too short to occupy both receptive sites. This similarity between succinyl- and acetyl-choline also explains its acetylcholine-like side-effects.