This element was discovered by F. Stromeyer in 1817 in Göttingen, Germany. The name comes from the Latin cadmia (calomine, a zinc carbonate). The element was isolated from impurities in calomine.

lonization energies

Cdl 9.0 eV, Cdll 16.9 eV, Cdlll 37.4 eV.

Absorption lines of Cdl

The equivalent width of the Cdl line 5085(2) in the sun is 0.0007.

Behavior in non-normal stars

Jaschek and Brandi (1972) detected Cdl and Cdll in one Ap star of the Cr–Eu– Sr subgroup.

Cdll was detected in two Am stars by Boyartchuk and Snow (1978) with ff(2265)=0.018. Sadakane (1991) found two Cdll lines (2144 and 2265, both of M.I) in the spectrum of another Am star. Isotopes Cd has eight stable isotopes – Cd 106, 108, 110, 111, 112, 113, 114 and 116, as well as 14 short-lived isotopes and isomers. In the solar system one finds respectively Cd 106 (1%), 108 (1%), 110 (12%), 111 (13%), 112 (24%), 113 (12%), 114 (29%) and 116 (7%).

Origin

Cd is produced by several processes: Cd106 and Cd108 by the p, Cd110 by the s, Cd116 by the r and Cd 111, 112, 113 and 114 by either the r or the s process.

This element was first isolated by H. Davy in London in 1808. The name comes from the Latin calx (lime).

lonization energies

Cal 6.1 eV, Call 11.9 eV, Calll 50.9 eV.

Ca is an element of great astrophysical importance. Lines of this element are seen in stars of practically all spectral types, except the hottest ones. If Call lines are visible in O– and B–type stars then they are due to the interstellar medium, or, more infrequently, to circumstellar envelopes.