This element was discovered in 1803 by W. Wollaston in London. The name comes from the Greek rhodon (rose).
Ionization energies
RhI 7.5 eV, RhII 18.1 eV, RhIII 31.0 eV.
Absorption lines of RhI
The RhI lines 3452(2) and 3188(4) in the sun both have an equivalent
width of 0.013. Gopka and Komarov (1990) measured Rh in one K5III star.
Behavior in non-normal stars
Jaschek and Brandi (1972) detected RhI in one Ap star of the
Cr-Eu-Sr subgroup.
Isotopes
Rh has one stable isotope, Rh103, and 19 short-lived isotopes
and isomers.
Origin
Rh is produced by both the r process and the s process.
Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.