Naming Ionic and Molecular compounds
Step 1: figure out if the compound is binary ionic or binary molecular or ionic.
Binary means only two different elements
Binary ionic compounds have one metal and one non-metal (NaF, CaCl2, Al2O3, Mg2C)
Binary molecular compounds have two non-metals (CH4, H2O, CO2, N3O5)
Ionic compounds (not binary ionic) have more then two elements (NaHCO3, Ca(NO3), Au(OH)3)
Binary ionic go to step 2A Ionic go to step 2B Binary molecular go to step 2C
Step 2A: Binary Ionic Metals (Group 1, 2, and 13)
1. Metal goes first and you get the name directly from the periodic table.
2. Non-metal goes second. The ending changes to “ide”
Name of element / Name at end of compound / Name of element / Name at end of compoundFluorine / Fluoride / Nitrogen / Nitride
Chlorine / Chloride / Oxygen / Oxide
Bromine / Bromide / Sulfur / Sulfide
Iodine / Iodide / Carbon / Carbide
Phosphorus / Phosphide / Hydrogen / Hydride
Binary Ionic Metals (Group 3 – 12) Stock system
1. Metal goes first and you get the name from the periodic table.
2. Immediately after the metal in brackets write the charge of the metal ion in roman numerals.
3. Non-metal goes second. The ending changes to “ide”
Element / Cations / Name of CationAntimony / Sb3+ / Antimony (III)
Sb5+ / Antimony (V)
Arsenic / As3+ / Arsenic (III)
As5+ / Arsenic (V)
Cobalt / Co2+ / Cobalt (II)
Co3+ / Cobalt (III)
Copper / Cu+ / Copper (I)
Cu2+ / Copper (II)
Gold / Au+ / Gold (I)
Au3+ / Gold (III)
Iron / Fe2+ / Iron (II)
Fe3+ / Iron (III)
Lead / Pb2+ / Lead (II)
Pb4+ / Lead (IV)
Manganese / Mn2+ / Manganese (II)
Mn4+ / Manganese (IV)
Mercury / Hg+ / Mercury (I)
Hg2+ / Mercury (II)
Nickel / Ni2+ / Nickel (II)
Ni3+ / Nickel (III)
Tin / Sn2+ / Tin (II)
Sn4+ / Tin (IV)
Titanium / Ti3+ / Titanium (III)
Ti4+ / Titanium (IV)
Binary Ionic Metals (Group 3 – 12) Classical system
1. Metal goes first. Some metals use special names. For all of them the ending changes to “ous” or “ic” (“ous” is for the lower ion of the metal, while “ic” is for the higher ion of the metal).
2. Non-metal goes second. The ending changes to “ide”
Element / Cations / Name of Cation /Element
/ Cations / Name of CationAntimony / Sb3+ / Antimonous / Lead / Pb2+ / Plumbous
Sb5+ / Antimonic / Pb4+ / Plumbic
Arsenic / As3+ / Arsenous / Manganese / Mn2+ / Manganous
As5+ / Arsenic / Mn4+ / Manganic
Cobalt / Co2+ / Cobaltous / Mercury / Hg+ / Mercurous
Co3+ / Cobaltic / Hg2+ / Mercuric
Copper / Cu+ / Cuprous / Nickel / Ni2+ / Nickelous
Cu2+ / Cupric / Ni3+ / Nickelic
Gold / Au+ / Aurous / Tin / Sn2+ / Stannous
Au3+ / Auric / Sn4+ / Stannic
Iron / Fe2+ / Ferrous / Titanium / Ti3+ / Titaniumous
Fe3+ / Ferric / Ti4+ / Titaniumic
Step 2B: Ionic compounds (Not binary)
1. Metal goes first and all previous rules for the metals apply
2. Negative polyatomic ion goes second and you get the name from the table below.
Name of
polyatomic ion / Ion formula /Name of
polyatomic ion / Ion formulaNitrite / NO2- / Hydrogen Carbonate (Bicarbonate) / HCO3-
Nitrate / NO3-
Sulfite / SO32- / Carbonate / CO32-
Sulfate / SO42- / Phosphate / PO43-
Chlorite / ClO2- / Acetate / C2H3O2-
Chlorate / ClO3- / Cyanide / CN-
Arsenite / AsO33- / Hydroxide / OH-
Arsenate / AsO43- / Ammonium / NH4+
Step 2C: Binary molecular 2 Non-metals
1. Generally the element closer to the top left hand corner of the periodic table is named first.
2. Then the second element is named. The ending changes to “ide”
3. To each of the elements you must add the proper prefix which indicates the amount of each atom.
Prefix / Number it represents / Prefix / Number it represents
Mono / 1 / hexa / 6
di / 2 / hepta / 7
tri / 3 / octa / 8
Tetra / 4 / nona / 9
Penta / 5 / deca / 10