<Ul> <Li> Dioxygen, O--colorless (faint blue) </Li> <Li> Ozone, O--blue </Li> <Li> Tetraoxygen, O--metastable </Li> <Li> Octaoxygen, O--red </Li> </Ul> <Li> Dioxygen, O--colorless (faint blue) </Li> <Li> Ozone, O--blue </Li> <Li> Tetraoxygen, O--metastable </Li>

Explain what allotropes are and give two examples