Chemically Talking, this molecule is "halfway" in between Sorbitan Oleate and Sorbitan Trioleate, meaning that it is also an attachment of sorbitan (a dehydrated sorbitol (sugar) molecule) with the unsaturated fatty acid Oleic Acid, but in a very ratio of 2:three that's why the "Sesqui" portion while in the molecule's name. Your personal knowledge