The study investigates the atomic structure of reduced graphene oxide (RGO) using high-resolution transmission electron microscopy (HRTEM). The researchers identify specific atomic-scale features in chemically derived graphene monolayers, which are the result of the oxidation-reduction treatment of graphene. The layers are composed of defect-free graphene areas with sizes of a few nanometers interspersed with defect areas dominated by clustered pentagons and heptagons. These defective areas maintain a planar sp²-configuration, making them undetectable by spectroscopic techniques. The study also observes that these defects introduce significant in-plane distortions and strain in the surrounding lattice. The findings provide insights into the detailed atomic structure of RGO, which is crucial for understanding its properties and potential applications. The results support the model proposed by Lerf and co-workers, suggesting that the oxidation-reduction process leaves disordered carbon inclusions within the sheets, seamlessly connected to the crystalline areas. The presence of topological defects and their effects on the material's properties are discussed, highlighting the need to account for these defects in comprehensive studies of RGO.The study investigates the atomic structure of reduced graphene oxide (RGO) using high-resolution transmission electron microscopy (HRTEM). The researchers identify specific atomic-scale features in chemically derived graphene monolayers, which are the result of the oxidation-reduction treatment of graphene. The layers are composed of defect-free graphene areas with sizes of a few nanometers interspersed with defect areas dominated by clustered pentagons and heptagons. These defective areas maintain a planar sp²-configuration, making them undetectable by spectroscopic techniques. The study also observes that these defects introduce significant in-plane distortions and strain in the surrounding lattice. The findings provide insights into the detailed atomic structure of RGO, which is crucial for understanding its properties and potential applications. The results support the model proposed by Lerf and co-workers, suggesting that the oxidation-reduction process leaves disordered carbon inclusions within the sheets, seamlessly connected to the crystalline areas. The presence of topological defects and their effects on the material's properties are discussed, highlighting the need to account for these defects in comprehensive studies of RGO.