One Common Ion Charge lithium fluorine Li + F LiF lithium fluoride Number of Atoms in Formula 2 lithium oxygen Li + O Li2O lithium oxide 3 sodium nitrogen Na N Na3N sodium nitride 4 magnesium chlorine Mg Cl MgCl2 magnesium chloride 3 calcium sulphur Ca S CaS calcium sulphide 2 strontium phosphorus Sr 2+ P Sr3P2 strontium phosphide 5 aluminum bromine Al 3+ Br AlBr3 aluminum bromide 4 silver nitrogen Ag + N Ag3N silver nitride 4 zinc iodine Zn I ZnI2 zinc iodide 3 cesium selenium Cs + Se Cs2Se cesium selenide 3 scandium sulphur Sc 3+ S Sc2S3 scandium sulphide 5 sodium oxygen Na + O Na2O sodium oxide 3 calcium fluorine Ca 2+ F CaF2 calcium fluoride 3 gallium iodine Ga 3+ I GaI3 gallium iodide 4 aluminum sulphur Al 3+ S Al2S3 aluminum sulphide 5 strontium nitrogen Sr 2+ N Sr3N2 strontium nitride 5 potassium phosphorus K K3P potassium phosphide 4 Elements to Combine Ions (optional) 2 + 2+ 2+ 2+ + 3 2 3 3 2 2 2 2 3 P 3 Formula Name Multiple Ion Charges 2+ Br FeBr2 iron(II) bromide Number of Atoms in Formula 3 3+ Br FeBr3 iron(III) bromide 4 + N Cu3N copper(I) nitride 4 3+ Cl AuCl3 gold(III) chloride 4 Pb 4+ P Pb3P4 lead(IV) phosphide 7 lead(II) sulphide Pb 2+ S PbS lead(II) sulphide 2 nickel(III) bromide Ni 3+ Br NiBr3 nickel(III) bromide 4 manganese(IV) sulphide Mn S MnS2 manganese(IV) sulphide 3 uranium(VI) iodide U I UI6 uranium(VI) iodide 7 rhenium(VII) fluoride Re 7+ F ReF7 rhenium(VII) fluoride 8 titanium(III) nitride Ti 3+ N TiN titanium(III) nitride 2 cobalt(II) oxide Co 2+ O CoO cobalt(II) oxide 2 copper(II) selenide Cu 2+ Se CuSe copper(II) selenide 2 gold(I) sulphide Au tin(IV) iodide Sn vanadium(V) phosphide V Elements to Combine Ions (optional) iron(II) bromide Fe iron(II) bromide Fe copper(I) nitride Cu gold(III) chloride Au lead(IV) phosphide 4+ 6+ 3 3 2 2 3 2 2 Formula Name + S Au2S gold(I) sulphide 3 4+ I SnI4 tin(IV) iodide 5 P V3 P5 vanadium(V) phosphide 8 5+ 2 3