March 2022

In 1987 Cernicharo and Guélin reported the detection of diatomic potassium chloride, KCl, toward the well-studied carbon star IRC +10216 (CW Leo) using the IRAM 30m telescope. More comprehensive spectroscopic data was published by Caris et al. in 2004 and Barton et al. in 2014. In 2019, Ginsburg et al. reported the detection of KCl toward the disk around Orion Source 1, including all four isotopologues formed from 39K, 41K, 35Cl, and 37Cl.

Researcher Links
J Cernicharo
M Guélin

Potassium chloride has a typical ionic bond, which is evident in the total density plot shown here. There is no covalent sharing of electronic charge between the nuclei. Potassium (left) has lost its valence 4s electron to chlorine (right), leaving both entities with spherical 3s2 3p6 configurations. Cl is slightly larger than Ar (the neutral 3s2 3p6 species), while K+ is slightly smaller.

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