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ZINC Zn Z = 30

This element was known in antiquity and used in brass. The name comes from the German name Zink.

Ionization energies
ZnI 9.4 eV, ZnII 18.0 eV, ZnIII 39.7 eV.

Absorption lines of ZnI

Table 1. Equivalent widths of ZnI 4810(2)
Group V III Ib
A2 0.03    
A7 0.015    
F0 0.075   0.036
F4 0.050    
F5 0.071   0.046
F6 0.069    
F8 0.060   0.114
G0 0.060    
G1 0.104    
G2 0.071,0.076    
S 0.080    
G8 0.068(IV)    
K0   0.085  
K2   0.082  
K5 0.067    

Zn I (see for instance the line at 4810) appears in A-type stars and grows slowly toward late types. No luminosity effect is visible.

Figure 62

Absorption lines of ZnII

Table 2. Equivalent widths of ZnII 2062(1)
Group V
B5 0.095(IV)
B7 0.115
A0 0.150

Source: Data are from Sadakane et al. (1988).

Behavior in non-normal stars
ZnII has its resonance lines at 2025(1) and 2062(1). Sadakane et al. (1988) studied the behavior of the 2062 line in Bp stars of the Hg-Mn subgroup. The line can be very strong (W up to 0.560), weak or absent. They find no clear relation to the behavior of the neighboring elements Cu and Ga. Cowley et al. (1974) detected Zn in Ap stars of the Cr-Eu-Sr subgroup in the photographic region.

Zn is strong in Am stars, the W values being stronger by a factor of about two than in normal stars of the same temperature (Smith 1973, 1974).

Sneden etal. (1991) found that Zn behaves like Fe and Ni in all metal-weak stars (disk and halo types). It can thus be considered a typical metal. Zn was detected in one iron-deficient (Fe / H = -5 dex) population two A-type star. This element does not share the iron abundance (W(4810, ZnI) = 0.030) (van Winckel et al. 1992).

Isotopes
Zn has five stable isotopes, namely Zn 64, 66, 67, 68 and 70, which in the solar system occur with frequencies of respectively 48%, 28%, 4%, 19% and 1%. There also exist ten short-lived isotopes and isomers.

Origin
All five Zn isotopes can be produced by the statistical equilibrium process. Zn 67, 68 and 70 can also be produced by the s process and Zn64 by explosive nucleosynthesis.


Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.

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