Column Descriptions

                                                                         
             Relative           Isotopic      Standard                   
Isotope      Atomic Mass        Composition   Atomic Weight    Notes     
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72  Hf  174  173.9400461(28)    0.0016(1)     178.49(2)         
        176  175.9414076(22)    0.0526(7)   
        177  176.9432277(20)    0.1860(9)   
        178  177.9437058(20)    0.2728(7)   
        179  178.9458232(20)    0.1362(2)   
        180  179.9465570(20)    0.3508(16)  
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