AT 56 5MG. AT 56, CAS Number: 162640-98-4, Molecular Formula: C25H27N5, Molecular Weight: 397. 52, Purity: greater than or equal to 98% by HPLC, Appearance: White solid, Synonym: 4-(5H-Dibenzo[a, d]cyclohepten-5-ylidene)-1-[4-(2H-tetrazol-5-yl)butyl]-piperidine, Size: 5MG