Atomic Weights and Isotopic Compositions for Helium
 Isotope   Relative
Atomic Mass 		    Isotopic
  Composition  		 Standard
Atomic Weight 		  Notes 
 
2 He 3     3.016 029 3201(25)   0.000 001 34(3)      4.002 602(2) g,r
4     4.002 603 254 13(6)   0.999 998 66(3)

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