# What are the empirical formulas for tetraphosphorous decaoxide (P4O10) and ethane (C2H6)?

Well ${P}_{2} {O}_{5}$ and $C {H}_{3}$....
The empirical formula is the SIMPLEST whole number ratio defining constituent atoms in a species. And here the species are (i) ${P}_{4} {O}_{10}$, and (ii) ${C}_{2} {H}_{6}$...so HALVE the molecular formulae...to get ${P}_{2} {O}_{5}$...and $C {H}_{3}$...