E.g. having benzoic acid [MolWeight (structure)=122.1213)] registered as three lots and versions: benzoic acid with 3xHCl, isotopic (1-13C)benzoic acid and benzoate 1xNa+, if we search for MF=C7H6O2, only the first version: benzoic acid with 3xHCl will be returned as result (salt info is not considered). See figure Search 10 .

Figure Search 10. Exact search using only the Formula field

Following the above example, if we initiate a substructure search using benzaldehyde as structure and the MolWeight (structure) > 121, all three lots (from different versions) are returned as search results ( figure Search 11 ). But, if using MolWeight (structure) > 122, only the first two versions are returned as results, since benzoate has an only 121.1134 for MolWeight (structure) and the salt (Na+ with multiplicity 1) is not considered. If a MolWeight (structure + salt/solvate) > 122 is initiated, again all three lots (from different versions) are returned as search results.

Figure Search 11. Substructure search using the structure and the MW (structure) field

Figure Search 12. Exact search using only the MW (structure + salt/solvate) field when searching for a user-supplied MW.