When divalent salts such as calcium chloride are dissociated in distilled water and agitated in an aqueous solution of GO, a complexation reaction occurs between the Ca2+ cations and the oxygen-containing functional groups, producing a continuous growing GO network due to the continuous bridging of the GO nanosheets by the divalent atoms tightly bonded by means of four oxygen atoms. Raman spectroscopy is frequently used to determine defects and ordered/disordered structures of graphene. The D band is recognized to be a disordered band originating in structural defects, edge effects and dangling sp2 carbon bonds that break the symmetry. The intensity ratio of the D band to the G band (ID/IG) is generally accepted as representative of the defect/disordered carbon structure. The effect of the reaction temperature and the type of divalent ions on the complexation reaction is shown in the Raman spectra (excitation with a 633 nm laser) in Fig 1A and 1B respectively. The GO complex networks synthesised show a very significant increase in the intensity of the D band with respect to that of GO. In addition, the ID/IG ratios of GO and cGO when crosslinked with Zn2+, Sr2+ and Ca2+ synthesised at 24°C are 0.96, 1.31, 1.25 and 1.11 respectively whilst the temperature of the reaction also had an effect and using calcium as the chelating agent the values were 1.17 and 1.26 at 34 and 55°C respectively. This clearly indicate an increase, demonstrating a significant level of disorder at the carbon edges due to the increase in defects and loss of symmetry arising due to the random bridging of the divalent atoms in the GO network. The intensity of these D-bands also decreases dramatically with increasing number of graphene layers, which indicates that crosslinking at the edges also occurs producing a 2D growth of the GO nanosheets interlinked by the divalent atoms. Thus, Fig 1 shows how the D-band intensity increases dramatically after the formation of the graphene oxide complexation networks and increasing temperature from 24 to 34°C indicate that the number of graphene layers decrease. The increase of the ID/IG ratios with increasing temperature, in spite of the broading of the G band due to the increase of the small D’ shoulder band, supports this last statement. This D’ shoulder appearing at around 1621 cm-1 in GO, related to the disorder of edge carbons, broadens on increasing the reaction temperature (Fig 1A) and when using different divalent salts (Fig 1B). This fact, once again, is in good agreement with the formation of complexation bonds at the edges. However, the D-band of Fig 1B shows that crosslinking of GO is much more effective using Zn2+ and Sr2+ at room temperature with ID/IG ratios, as mentioned, close to that obtained with Ca2+ at 55°C.