A data frame that contains at least information on ChEBI IDs (id) and their names (name). This data frame can be obtained by calling fetch_chebi(). Ideally this should be subsetted to only contain molecules of a specific type e.g. metals. This can be achieved by calling find_all_subs with a general ID such as "25213" (Metal cation) and then subset the complete ChEBI database to only include the returned sub-IDs. Using a subsetted database ensures better search results. This is a helper function for other functions.

A character vector that contains names or name patterns of molecules. Name patterns can be for example obtained with the split_metal_name function.