A lack of nickel or tectonic event are two theories for this element's namesake "catastrophe," or its precipitous increase in the atmosphere millions of years after the development of photosynthetic plants.
The solid red epsilon phase of this material has been shown to be a crystal of eight-atom molecules, and its singlet state has been observed in reactions with enzymes such as chloroperoxidase. Its singlet state can also mediate Diels-Alder and other -ene reactions, and this element undergoes a cycle with fluorine in certain massive stars. A lack of nickel or tectonic event are two theories for this element's namesake "catastrophe," or its precipitous increase in the atmosphere millions of years after the development of photosynthetic plants. For 10 points, this is what element of atomic weight 16, symbolized O?
The solid red epsilon phase of this material has been shown to be a crystal of eight-atom molecules, and its singlet state has been observed in reactions with enzymes such as chloroperoxidase.
{oxygen}