The solvent-exchange process can be subclassified based on the last exchange-solvent used before the evacuation (Figure ). For the successfully activated MOFs, acetone is quite popular to replace the synthesis solvent, while dichloromethane (also known as methylene chloride or methylene dichloride with a chemical formula CH2Cl2) and methanol come in the second place. Unusually, dichloromethane is preceded with methanol wash or exchange, and in few cases a mixture of dichloromethane and methanol was used (co-exchange solvents). Other less frequently used solvents are ethanol, chloroform (aka trichloromethane, with a chemical formula CHCl3), acetonitrile (abbreviated as MeCN, with a chemical formula CH₃ CN). Also, among the MOFs, one structure was activated from tetrahydrofuran (also known as oxolane, with a chemical formula (CH₂) ₄O). In contrast, due to the small number of the collapsed MOFs, reliable statistical results could not be presented. It is worth to mention that in few cases a mixture of solvent was used as exchange-solvents. In addition, in fewer cases among the many used solvents, it was difficult to identify what was the last used solvent. Thus, both above cases were excluded from the statistics presented in Figure .