In this work a method is developed to electrochemically synthesize 2D metal-oxide within the framework of laminar graphene oxide. Through purposeful use of the angstrom confinement which reduced graphene oxide provides, the synthesis of the 2D metal oxide is spatially limited to two dimensions. We further show that confinement results in a sub-unit cell structure with oxygen and chromium vacancies. With that our work successfully combines the fields of angstrom confined chemistry, electrochemistry and 2D materials.