“…In Fig. S4,† the cutoff edge of CsSbPO is about 213 nm (corresponding to a band gap of 5.82 eV using the Kubelka–Munk equation), which is comparable to the ones of other phosphates, such as LiMP 2 O 6 (M = Rb, Cs) (<210 nm), 78 LiZnP 3 O 9 (204 nm), 79 CsPbP 3 O 9 (<220 nm), 80 K 2 RbSc(PO 4 ) 2 (<207 nm), 81 K 3 Al 2 (PO 4 ) 3 (238 nm), 82 and (H 3 O)Ca 2 Zn 3.5 (PO 4 ) 4 (218 nm). 83 The results speculate that CsSbPO can be used as potential UV optical materials.…”