We are asked to determine the subscript of ammonium in the chemical formula of an ionic compound with polyatomics, ammonium dichromate.
A binary ionic compound with polyatomics has the following features:
- A metal or a positive polyatomic species (Cation)
- A nonmetal or negative polyatomic species (Anion)
Rules for Naming:
1. The metal or the positive polyatomic species is named and written first.
If the metal is a transition metal, we must use a Roman Numeral to describe its positive charge.
2. The nonmetal retains its base name followed by the suffix -ide while the negative polyatomic species retains its name.