We present a theoretical investigation on the structures and properties of Ti2Si20-/0 clusters using density functional theory calculations. The results showed that the global minima of both anionic and neutral Ti2Si20 adopt a C-2h symmetric double hexagonal prisms stacked structure with the two Ti atoms encapsulated inside the silicon cage. Bond length, Wiberg bond order, constant electronic charge density, and molecular orbital analyses suggest that the Ti-Ti interactions in Ti20Si20-/0 are weak. Interestingly, Ti2Si20-/0 exhibit significant 3D aromaticity, which play important roles in their structural stability. (C) 2018 Elsevier B.V. All rights reserved.