1,3,5-Trithiacyclohexane 1,3,5-Trithiane 291-21-4 Formaldehyde, thio-, trimer NSC1937 Thioform Trimethylene trisulfide Trimethylentrisulfid Trithioformaldehyde WLN: T6S CS ESTJ s-Trithiane sym-Trithian