forming hydrogen bonding with the chiral HBDs. Only three of the eleven HBAs in the database are chiral, L-proline, L-menthol and (S)-acetoxypropionic acid, not shown in Table . The majority of the eutectic mixtures in the database have been developed by mixing an achiral HBA with a chiral HBD. Only TBACl and thymol have melting points below 55 °C, and therefore, will melt at the high temperature in the shaker/incubator. This improves the effectiveness of the mixing in the well plate, and may increase the likelihood of forming a liquid at the higher temperature (55 Figure shows a comparison of the HBA:HBD combinations attempted vs. combinations that resulted in liquid formation at room temperature (20 °C), and Figure shows the comparison based on the identity of the HBA:HBD combination. The most effective HBA for forming liquids at room temperature was TBACl with ~45% of its molar ratios (Figure ) and ~60% of the HBA:HBD combinations successful at forming liquids. As a comparison, both TBACl and ChCl were screened with the same number of HBDs, but only ~25% of the ChCl:HBD ratios were liquid at room temperature. Both TBACl and ChCl are hygroscopic salts, but the difference in successful a b ratios indicates that the absorption of environmental water is not the only factor determining which combinations form liquids at room temperature. Direct comparison of the TBACl results with any of the other HBAs is complicated by the difference in the number of combinations studied. For example, TEACl and TBABr were introduced as HBAs to facilitate structural comparisons after it was evident that TBACl was the most successful HBA. This means that many of the unsuccessful TBACl:HBD combinations have not been attempted with TEACl and TBABr. This means that the comparison of successful TEACl:HBD and TBABr:HBD combinations (Figure ) overemphasize successful HBDs as compared to TBACl and ChCl. Figure also shows that thymol is successful as an HBA with ~45% of thymol:HBD combinations (Figure ) as liquids at room temperature. HBD components. As of this writing, the database has 93 unique HBDs that were combined with one or more of the 10 HBAs. All but two of the HBDs in the database are have at least one chiral carbon center. Among the 93 HBDs there is considerable structural diversity, but most include functional groups that can act as hydrogen bond donors, including acids, alcohols, amines, and amides. There are 32 combinations of HBA-HBDs that includes 24 unique HBDs that were liquid at room temperature for every ratio attempted. Table lists the HBDs and HBAs that successfully formed liquids at all ratios. There is enough structural diversity among the 24 HBDs in Table that makes it difficult to rationalize liquid formation of the mixtures based on the structure. However, the one common feature of the HBDs in Table is that they have relatively low melting points, or are already liquids at room temperature. Ten of the 24 HBDs in Table start as liquids at room temperature (shown in red in Table ) before mixing, whereas the remaining 14 HBDs are solids, but only three have a melting point > 100 °C. For many of these HBDs, even modest depression of the melting point will result in liquids at room temperature, 20 °C. The majority (21 out of 32) of the combinations in Table include TBACl as the HBA, which is consistent with the data in Figure that shows TBACl as the most effective HBA for liquid formation.