Unsuitability of ¹²C₆₀ as a standard of atomic weight

A critical discussion is given of the suggestion by Dougherty et al. (J. Am. Soc. Mass Spectrom. 1994, 5, 120) that the ¹²C₆₀ molecule replace the ¹²C atom as the primary standard of atomic mass. Adoption of the proposed standard would require that the unified atomic weight/mass scale, finally achieved with much difficulty in 1960, be abandoned without demonstrable benefit. Furthermore, the proposed standard has a molecular mass that is inherently ambiguous at a level that makes it unacceptable for that purpose.