Theoretical prediction for growth behavior and electronic properties of monoanionic Ru2Gen− (n = 3–20) clusters

•A detailed study on the structural and electronic properties of monoanionic Ru2Gen− (n = 3–20) clusters using comprehensive genetic algorithm combined with density functional theory.•One extra electron influences the geometric structures of Ru2Gen clusters to compare with their neutral ones.•Ru2Ge10−, Ru2Ge12− and Ru2Ge14− clusters have relatively higher structural and chemical stability.