Quantification of nanoconfined interlayer molecules (water, or organic pillars) is conducted using thermogravimetric analysis (TGA, Fig. ). Heating to 600 °C in synthetic air atmosphere converts H2Ti4O9 into 4 TiO2 by dehydration/dehydroxylation (corresponding to 94.7 % of the initial mass). At the same time, there is a complete removal of nanoconfined molecular species by combustion and/or evaporation, hence any additional mass loss can be attributed to interlayer molecules. For pristine HTO, an overall mass loss of 10.1 % is measured, indicating an initial composition with a structural formula H2Ti4O9•0.99H2O. The measured overall mass loss for HTO-PA is 24.7 %, indicating the initial composition H2Ti4O9•1.47PA, and for HTO-HDA it is 28.8 % suggesting the structural formula H2Ti4O9•0.96HDA. Hence it is reasonable to approximate the nanoconfined interlayer chemistry of HTO, HTO-PA and HTO-HDA as 1 H2O, 1.5 PA and 1 HDA molecules, respectively. These values are further utilized for theoretical calculation of the structure.