CAS: 51694-22-5 EC No: 257-350-4 MDL No: MFCD00043146 UN No: UN3283; Haz Class: 6.1; Packing Group: II Crystalline/Solid Molecular Formula: C₇H₄N₂O₂Se MW: 227.08 Melting Point: 140-142°

CAS: 630-10-4 EC No: 211-129-9 MDL No: MFCD00008065 UN No: UN3283; Haz Class: 6.1; Packing Group: II Crystalline/Needles Linear Formula: (H₂N)₂C=Se MW: 123.02 Melting Point: 210-215° (decomposes)