Here is an overview of the guidelines for naming and writing formulas for several types of compounds.
Some names and formulas for compounds can be constructed from general rules, but others must be memorized. The following list includes some commonly encountered names and formulas that must be memorized.
water - H2O
ammonia - NH3
methane - CH4
ethane - C2H6
propane - C3H8
methanol - CH3OH
ethanol - C2H5OH
2-propanol (isopropyl alcohol) - C3H7OH
The general procedure for naming other compounds consists of two steps:
Step #1: Decide what type of compound the name or formula represents.
Step #2: Apply the rules for writing the name or formula for that type of compound.
The following summarizes the distinguishing features of different kinds of formulas and names.
General Formula - AaBb - For example, N2O5 or CO2
General Name - (prefix unless mono)(name of first element in formula) (prefix)(root of second element)ide - For example, dinitrogen pentoxide or carbon dioxide
General Formula - MaAb - F or example, NaCl or FeCl3
General Name - (name of metal) (root of nonmetal)ide or (name of metal)(Roman #) (root of nonmetal)ide - For example, sodium chloride or iron(III) chloride
General Formula - MaXb or (NH4)aXb X = recognized formula of polyatomic ion - For example, Li2HPO4 or CuSO4 or NH4Cl or (NH4)2SO4
General Name - (name of metal) (name of polyatomic ion) or (name of metal)(Roman #) (name of polyatomic ion) or ammonium (root of nonmetal)ide or ammonium (name of polyatomic ion) - For example, lithium hydrogen phosphate or copper(II) sulfate or ammonium chloride or ammonium sulfate
General Formula - HX(aq) - For example, HCl(aq)
General Name - hydro(root)ic acid - For example, hydrochloric acid
General Formula - HaXbOc - For example, HNO3 or H2SO4 or H3PO4
General Name - (root)ic acid - For example, nitric acid or sulfuric acid or phosphoric acid
The following links take you to pages that have more information about writing names and formulas for compounds.
Binary Covalent Nomenclature
Cation Names and Formulas
Anion Names and Formulas