Naming Inorganic Compounds

Naming Inorganic Compounds

Names and Formulas of Ionic Compounds
• Chemical nomenclature – naming of substances.
• Divided into organic compounds (those containing C, usually in combination with H, O, N, or S) and inorganic compounds (all other compounds)

1. Positive Ions (Cations)
• Cations formed from a metal have the same name as the metal
 Example: Na1+ = sodium ion
• If the metal can form more than one cation, then the charge is indicated in parentheses in the name.
 Examples: Cu1+ = copper (I); Cu2+ = copper (II) [Stock system]
• Cations formed from nonmetals end in –ium.
 Example: NH41+ ammonium ion

2. Negative Ions (anions)
• Monatomic anions (with only one atom) use the ending –ide.
Example: Cl1- is chloride ion

• Some simple polyatomic anions also have the ending -ide; hydroxide, cyanide, and peroxide ions.
• Polyatomic ions (with many atoms) containing oxygen are called oxyanions.
 These end in –ate or –ite. (The one with more oxygen uses –ate.)
 Examples: NO31- is nitrate, NO21- is nitrite.

• Polyatomic anions containing oxygen with additional hydrogens are named by adding hydrogen or bi (one H), dihydrogen (two H), etc. to the name, as follows:
 CO32- is the carbonate anion
 HCO3 is the hydrogen carbonate (or bicarbonate) anion
 H2PO4 is the dihydrogen phosphate anion


3. Ionic Compounds
• These are named cation and anion
 Example: BaBr2 = barium bromide


Names and Formulas of Acids

• The names of acids are related to the names of anions:
 -ide becomes hydro- ...-ic acid; Examples: HCl hydrochloric acid
 -ate becomes –ic acid; HClO4 perchloric acid
 -ite becomes –ous acid. HClO hypochlorous acid


Names and Formulas for binary Molecular Compounds

• Binary molecular compounds contain two elements.
• The most metallic element (i.e., the one farthest to the left on the periodic table) is usually written first. Exception: NH3 (ammonia)
• If both elements are in the same group, the lower one is written first.
• Greek prefixes are used to indicate the number of atoms (e.g. mono, di, tri).
 The prefix mono is never used with the first element (i.e., carbon monoxide, CO).
 Examples:
• Cl2O dichlorine monoxide
• N2O4 dinitrogen tetroxide
• NF3 nitrogen trifluoride
• P4S10 tetraphosphorus decasulfide



CHEMISTRY The Central Science 8th Edition Brown, LeMay, Bursten Ch 2: Atoms, Molecules, and Ions