# What is "ammonium dichromate?"

Well, it is crystalline ${\left(N {H}_{4}\right)}_{2} C {r}_{2} {O}_{7}$.
Ammonium dichromate is the ammonium salt of the dichromate ion, $C {r}_{2} {O}_{7}^{2 -}$, which is a powerful oxidant, and used extensively for this purpose in organic chemistry.