The atomistic model of the C-S-H nanofoil as proposed by Casar et al. and a 2D schematic of the 3 layer, 2 interlayer thick C-S-H nanofoil are shown in Figure . From the current understanding of the C-S-H structure, 4 unique Ca sites can be identified: mainlayer, bridging, pairing, and surface. Each of these sites reflects a different structural environment of the Ca atom and therefore is expected to have a distinct Ca chemical shift . However, a lack of symmetry is expected, and therefore broadening by the second-order quadrupolar interactions is anticipated . The possible Ca sites in the C-S-H nanofoil are shown in Figure and are then described in detail below.