SEM and EDS analyses were performed to investigate the crystal-glass microstructure and the chemical composition of the composites. Two pieces of each sample were analysed, each from markedly different orientations of the pelletised composite (Fig. , Fig. ). First, a horizontal orientation was analysed to explore the surface of the pellet. This indicated a rough surface containing different domains. Small cuboctahedra can be distinguished as ZIF-8 crystallites, which are partially embedded in smooth inorganic glass domains. Moreover, several minor cracks between domains were highlighted by mapping (Fig. ). The presence of ZIF-8 is more evident in the case of [(ZIF-8)0.3(IG)0.7] MOF-CIGC due to the higher proportion of ZIF material in the composite. To ensure proper representation of the bulk sample, pieces from a vertical orientation of the pellet were examined (Fig. , Fig. ). ZIF-8 crystallites were clearly embedded within the inorganic glass matrix. EDS analyses were carried out in five different points of ~300 µm 2 per sample to determine the percentage of Na, P and Zn (Fig.