Gallium Chloride Oxide: Structure Validation of a Direct Wide Bandgap Semiconductor

Gallium chloride oxide (GaClO) was synthesised, and its crystal structure was validated using powder X‐ray diffraction, UV/VIS, NMR, and quantum chemical calculations at the level of density functional theory under periodic boundary conditions. Experimental data confirm a layer‐like orthorhombic structure in space group ( P c a 21) with the lattice parameters a = 5.662 Å, b = 8.343 Å, and c = 5.087 Å and show that GaClO is a new structure type. Electronic structure calculations at density functional theory level using a screened hybrid functional indicate that GaClO is a wide bandgap semiconductor featuring a direct bandgap of E g = 4.4 eV, while a value of 3.8 eV was estimated from diffuse reflection measurements.