Oxygen dissolution and surface oxide reconstructions on Nb(100)

•The surface crystallographic orientation of Nb dictates the long-range order of the native oxide.•The energetics for oxygen dissolution on NbO/Nb(100) were determined.•The structural evolution of the NbO/Nb(100) was elucidated as a function of thermal annealing using scanning tunneling microscopy.•The oxygen dissolution kinetics have bearing on superconducting radio frequency (SRF) processing procedures.