Column Descriptions Relative Isotopic Standard Isotope Atomic Mass Composition Atomic Weight Notes _________________________________________________________________________ 96 Cm 243 243.0613893(22) 244 244.0627528(19) 245 245.0654915(22) 246 246.0672238(22) 247 247.0703541(47) 248 248.0723499(56) _________________________________________________________________________NIST | Physical Measurement Laboratory | Physical Reference Data | Atomic Weights and Isotopic Compositions Main Page