Fig. also shows that at OCP, 𝜒 ?#@ (;) is ~1.1 x 10 -22 m 2 V -1 . This non-zero value is attributed to the net aligned dipoles from the interfacial NiOH, NiO -, and NiOH2 + groups. Its positive value indicates a net "up" orientation of the interfacial dipoles, i.e. the positive end (Ni 2+ ) pointing into the electrode and the negative end (OH, O -, or OH2 + ) pointing into the electrolyte. This interpretation is consistent with SHG results from colloidal and macroscopically flat surfaces showing that positively (resp., negatively) signed values of 𝜒 (;) correspond to water dipoles pointing their negative end (oxygen) away from (resp., towards) the surface. Fig. Speelman and Geiger page 7