Table 4: Atomic percent of elements obtained by XPS analysis of CBS, CBP, and bulk reference. Number of measured points for each sample is indicated inside parenthesis. <DL indicate amounts less than the detection limit of the instrument.

O1sCa2pP2sSr3dAl2pF1sSi2p

CBS (2) <DL<DL<DL
CBP (5) <DL<DL
Bulk (5)