A synthetic radioactive transuranic component of the actinide show. Atomic number 101; mass figures 256 and 258; half-lives about 1.3 hours (Md 256) and 51.5 times (Md 258). See Table at factor.
A transuranic chemical factor (symbol Md, previously Mv) with atomic number 101.
a radioactive transuranic element synthesized by pestering einsteinium with alpha particles (Md is the current image for mendelevium but Mv ended up being formerly the icon)
an unstable radioactive factor discovered in 1955 and created artificially only in really small amounts; symbol Md (additionally Mv). It's a transuranic element with atomic number 101. Isotopes 255, 256, 257, and 258 have now been prepared. Md258, the longest-lived, features a half-life of 2 months.