In previous studies, we have investigated the nucleation of TDMAH on pristine Co3O4(111) and on Co 3 O 4 (111) covered by functionalized (OH-terminated) and non-functionalized (hydrocarbon-terminated) self-assembled monolayers (SAMs). In both studies, we found that the presence of OH groups, or more precisely acidic protons, is essential for nucleation. On the hydrocarbon-terminated SAM, nucleation and, thus, ALD of HfS2 were completely suppressed due to the lack of reactive nucleation sites. Accordingly, one would expect no nucleation on CoO(100) due to the lack of acidic protons on the surface above 360 K. However, the ALD process is not suppressed, but it proceeds homogenously suggesting fast and efficient nucleation. In the following, we will scrutinize the first half cycle in more detail in order to identify how the nucleation proceeds on the CoO(100) surface.