Column Descriptions Relative Isotopic Standard Isotope Atomic Mass Composition Atomic Weight Notes _________________________________________________________________________ 66 Dy 156 155.9242847(17) 0.00056(3) 162.500(1) g 158 157.9244159(31) 0.00095(3) 160 159.9252046(20) 0.02329(18) 161 160.9269405(20) 0.18889(42) 162 161.9268056(20) 0.25475(36) 163 162.9287383(20) 0.24896(42) 164 163.9291819(20) 0.28260(54) _________________________________________________________________________NIST | Physical Measurement Laboratory | Physical Reference Data | Atomic Weights and Isotopic Compositions Main Page