A team of researchers from Fudan University and Nanjing Tech University, both in China, has demonstrated that the 18-electron principle is not limited to transition metals. In their paper published in the journal Science, the group describes their work with calcium, strontium and barium atoms and what they found. P. B. Armentrout with the University of Utah offers a Perspective piece on the work done by the team in China in the same journal issue.