For Ga@SiO2, distinguishing between sites in the absence of probe molecules using 71 Ga NMR is more challenging, and the spectrum is dominated by one species, associated with a small CQ (15 MHz), This work demonstrates the challenges in characterizing Ga surface sites, such as those found in Ga@SiO2, directly from 71 Ga NMR in the absence of probe molecules. Furthermore, this work also shows that probe molecules are not only useful for indirectly observing Ga sites by, for example,