The disruption of H 2 O structures gives rise to an increase in entropy that reflects the increase in the number of accessible microstates of the system. Values of ΔS HB within Ti-FAU are similar that of bulk H 2 O, which reflects the three-dimensional H 2 O clusters (~1.3 nm) that form within the supercages of FAU. ΔS HB values within Ti-FAU do not depend on the density of (SiOH) x , likely because the HBs within these supercages primarily reflect bonds between H 2 O molecules, rather than with (SiOH) x defects (Table ). The disruption of H 2 O within Ti-MFI leads to ΔS HB that are ~12 J mol -1 K -1 greater than Ti-BEA. The greater values of ΔS HB for H 2 O in 0.55 nm pores of Ti-MFI reflect lesser <N HB > compared to those in the 0.65 nm pores of Ti-BEA. Values of ΔS HB also decrease slightly with [(SiOH) x ] for a given zeolite framework, which suggests that (SiOH) x defects provide a stabilizing interaction when HB among H 2 O molecules are disrupted. The differences of ΔS HB among all these zeolite structures may be envisioned as cutting strands of a rope. Within bulk water and Ti-FAU, the ropes possess multiple strands that bind H 2 O molecules even when a single strand fails. In contrast, ropes within Ti-MFI, and to a lesser extent Ti-BEA, contain fewer strands and the loss of a single one may allow H 2 O molecules to break free. Si-CDO-OH differs considerably: measured values of ΔS HB (and ΔH HB ) are nearly zero because a HB between H 2 O and a silanol group replaces each HB lost between H 2 O molecules due to significant spatial confinement within these 0.45 nm pores.