  Two-dimensional (2D) antimony, so-called antimonene, can form antimonene
oxide when exposed to air. We present different types of single- and few-layer
antimony oxide structures, based on density functional theory (DFT)
calculations. Depending on stoichiometry and bonding type, these novel 2D
layers have different structural stability and electronic properties, ranging
from topological insulators to semiconductors with direct and indirect band
gaps between 2.0 and 4.9 eV. We discuss their vibrational properties and Raman
spectra for experimental identification of the predicted structures.
