Chemically speaking, this molecule is "midway" involving Sorbitan Oleate and Sorbitan Trioleate, indicating 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 two:3 therefore the "Sesqui" element in the molecule's identify. The emollient plant oil co