Column Descriptions Relative Isotopic Standard Isotope Atomic Mass Composition Atomic Weight Notes _________________________________________________________________________ 62 Sm 144 143.9120065(21) 0.0307(7) 150.36(2) g 147 146.9149044(19) 0.1499(18) 148 147.9148292(19) 0.1124(10) 149 148.9171921(18) 0.1382(7) 150 149.9172829(18) 0.0738(1) 152 151.9197397(18) 0.2675(16) 154 153.9222169(20) 0.2275(29) _________________________________________________________________________NIST | Physical Measurement Laboratory | Physical Reference Data | Atomic Weights and Isotopic Compositions Main Page