I'm trying to think of a specific word that I came across in my organic lab class a few semesters ago. We were doing structure elucidation using TLC, melting temp, etc...and somewhere I read a word that I had never seen before and I'm pretty sure it's a word used primarily in chemistry. The definition of the word is something like this: a compound or chemical that is strongly thought or suspected to have a particular identity/structure but that requires identification procedures to confirm that identity/structure. And I can't remember if it's a noun or an adjective. If it's an adjective, the closest synonyms that I can think of are tentative and suspected. If used in a sentence it would be like, "Identification methods were used to confirm the identity of the ________ product." If it's a noun, the closest synonyms I can think of are candidate and suspect. If used in a sentence it would be like, "Identification methods were used to confirm the identity of the _______." I'm trying so hard to remember what this word is but it's just not coming to me. I feel like it maybe starts with an "a" or a "t" or has those letters in it.