P2O4\mathrm{P}_{2} \mathrm{O}_{4}P2O4
P2O5\mathrm{P}_{2} \mathrm{O}_{5}P2O5
H3PO2\mathrm{H}_{3} \mathrm{PO}_{2}H3PO2
Ca3P2\mathrm{Ca}_{3} \mathrm{P}_{2}Ca3P2