- Rigel (stars.astro.illinois.edu)
RIGEL (Beta Orionis). Like its class M reddish rival in Orion, Betelgeuse, Rigel (Beta Orionis) is a supergiant, though a contrasting blue one (actually more blue-white) of class B (B8).
- Chlorine (Wikipedia)
Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.