PZC(and so pK): mean value of [BPQBP80], [ZA88] and [HV96]; for 0.01 M NaNO3, pH 3-11; CD-MUSiC; SSD: assumption mixture of 10% 021 face (7.4 sites/nm^2) and 90% 110 face (6 sites/nm^2): total 6.15 sites/nm^2; symmetric ion pair formation for both singly and triply coordinated surface groups: overall Stern layer capacitance 0.9 F/m^2