Inhibition effect of sparteine isomers with different stereochemical conformations on the corrosion of mild steel in hydrochloric acid solution

•The inhibition efficiency of (−)-Sparteine is higher than that of (+)-Sparteine.•Proposing adsorption property controlled by the chemical and stereoscopic structure.•Find the relationship between stereoscopic structures and inhibition performances.•The guidance for the discovery of new inhibitors with desirable inhibition effects.