Graphite and diamond come under covalent structure.
In order to obtain the empirical formula, first divide each
element by its molar mass which can be found in the periodic table. The answer
in the first step would be the number of moles of each element. Then divide
each element with the lowest number of moles obtained in the first step in this
case Phosphorus had the lowest number of moles. Then round it up to the nearest
whole number. The empirical formula then is Phosphorus pentafluoride or PF5.
The answer is, C: both Erin and Chris are correct.