An earlier proposed method for the estimation of critical data of metals wi
th extrapolated Vapor pressure curves does not work with uranium. This stro
ngly indicates the problems of such high-temperature extrapolations with th
e available vapor pressure data. Thus, various similarity relations for the
critical data have been discussed. As most reliable values the critical te
mperature T-c = 9000 K and pressure p(c) = 5000 bar have been chosen. With
these values a two-term vapor pressure equation has been constructed.