6 8 G d ▁| ▁style =" text - align : right " ▁| ▁ 6 4 ▁| ▁style =" text - align : right " ▁| ▁ 1 0 4 ▁| ▁ 1 6 7 . 9 4 8 3 6 ( 7 5 ) # ▁| ▁ 3 0 0 #   ms ▁| ▁ β − ▁| ▁ 1 6 8 T b ▁| ▁ 0 + ▁| ▁| ▁| - ▁| ▁ 1 6 9 G d ▁| ▁style =" text - align : right " ▁| ▁ 6 4 ▁| ▁style =" text - align : right " ▁| ▁ 1 0 5 ▁| ▁ 1 6 8 . 9 5 2 8 7 ( 8 6 ) # ▁| ▁ 1 # ▁s ▁| ▁ β − ▁| ▁ 1 6 9 T b ▁| ▁ 7 / 2 − # ▁| ▁| ▁ ▁References ▁▁▁ ▁Is ot ope ▁masses ▁from : ▁▁▁ ▁Is ot op ic ▁compos itions ▁and ▁standard ▁atomic ▁masses ▁from : ▁▁▁▁▁ ▁Half - life , ▁spin , ▁and ▁is omer ▁data ▁selected ▁from ▁the ▁following ▁sources . ▁▁▁▁▁▁▁ ▁Category : G ad olin ium ▁▁ ▁G ad olin ium <0x0A> </s> ▁Iz ak ▁Ste phan us ▁de ▁Vill iers ▁Sw art ▁( born ▁Mal mes bury , ▁ 1 8 ▁May ▁ 1 9 6 4 ), ▁known ▁as ▁Bal ie ▁Sw art ', ▁is ▁a ▁former ▁South ▁African ▁rugby ▁union ▁footballer . ▁He ▁played ▁as ▁a ▁prop ▁( 1 . 8