In article number 2100009, Gustavo M. Dalpian, Hannes Raebiger, and co-workers report the discovery of a family of 2D electride materials with composition M2CO2, where M = Sc, Y, La, Lu, Tm, and Ho. The electride behavior emerges in a new structural phase for MXenes, where the hexagonal carbon layer is broken up into C3 trimers, and anionic electrons get trapped in the voids between the C3 units.
