Naming Inorganic

Compounds

Naming• There are almost an infinite number of ways in

which element can combine in order to make

compounds

• Therefore, a systematic method is used so that we

can easily name all compounds

• We will focus on naming inorganic (all non-carbon

containing) compounds in this lecture

Names and Formulas of Ionic Compounds:

Cations1. Cations formed from metal atoms have the same name

as the metal

o E.g.: Na+ is a sodium ion, Zn+2 is a zinc ion, etc.

2. If a metal can have multiple charges, the positive charge

is indicated by a Roman numeral in parentheses

following the name of the metal.

o E.g.: Fe2+ = iron (II) ion, Cu+3 = copper (III) ion

o Iron, cobalt, copper, tin, and lead are the most

common metals that have multiple charges

REMEMBER – MEMORIZE

YOUR POLYATOMIC IONS!

Names and Formulas of Ionic Compounds: Anions1. The names of elements that are anions are formed

by adding –ide to the end of the name

o Cl- = Chloride ion

o Br- = Bromide ion

o O2- = Oxide ion

Names and Formulas of Ionic Compounds: Anions2. Polyatomic ions that contain oxygen have names

ending in either –ate or –ite

NO3- = Nitrate

NO2

- =Nitrite

SO42- = Sulfate

SO3

2- = Sulfite

-ate ending polyatomic have more oxygens

than –ite ones!

Names and Formulas of Ionic Compounds: Anions• Sometimes oxygen binds to the same ion with

increasing amount of oxygens (e.g. ClO4-, ClO3

-,

etc.)

• These come in 4’s and the pattern is always:

o Per_____ate = 4 oxygens

o _______ate = 3 oxygens

o _______ite = 2 oxygens

o Hypo______ite = 1 oxygen

• Example:

o ClO4- = Perchlorate, ClO3

- = Chlorate, ClO2- =

Chlorite, ClO- = Hypochlorite

Names and Formulas of Ionic Compounds: Anions3. Anions derived by adding H+ to an oxygen

containing anions have the prefix of hydrogen or

dihydrogen based on the number of H+ in the anion

Naming Ionic Compounds

• To name ionic compounds, you always name the

cation and then the anion.

Class ExampleName the following

compounds:

1. CaCl22. Ba(OH)2

3. Sodium hydroxide

Try It Out!1. K2SO4

2. FeCl33. Cobalt (II) Nitrate

Names and Formulas for Acids

• Recall, acids are compounds that donate a

hydrogen ion to solution.

• Acids are named differently than other compounds

• Two rules when naming acids:

1. Acids containing anions that are only single

elements are named by changing the –ide

prefix on the anion to –ic and adding hydro in

front of the anion and then adding acid at the

end.

• E.g. HCl is hydrochloric acid

2. Acids containing polyatomic ions are named by

changing –ate to –ic and –ite to –ous on the

anion and then adding acid at the end

Class Example1. HBr

2. H2SO4

3. HClO2

Try It Out!1. HNO3

2. HF

Naming Covalent Molecules (Non-Acids)

• The process for naming covalent inorganic

compounds requires the following rules:

1. The name of the element furthest

left on the Periodic Table is written

first

2. If both elements are in the same

group, the larger one is written 1st

3. The name of the second element

is given an –ide ending

4. Greek prefixes are used to show

the number of atoms

Prefix Meaning

Mono- 1

Di- 2

Tri- 3

Tetra- 4

Penta- 5

Hexa- 6

Hepta- 7

Octa- 8

Nona- 9

Deca- 10

Class Example1. SiBr4

2. Disulfur dichloride

3. NH3

Try It Out!1. N2O

2. Tetraphosphorus hexasulfide

Naming Compounds Flow Chart

Does the Formula begin with H

NO YES

Does it begin with a metal which has more than

one oxidation number? (e.g.; Fe, Ni, Cu, Sn, Hg)

NO YES

Name the first element

followed by its oxidation number (Roman numeral)

Does the formula contain a polyatomic ion?

NO YES

Are both elements nonmetals?

NO YES

Name the first element, Then the second element

With the –ide ending.

Name the first element

using the proper prefix. (never mono-). Name the

second element with the proper prefix (including

mono- and –ide ending. 1 mono-

2 di- 3 tr-

4 tetra- 5 penta-

6 hexa- 7 hepta-

8 octa- 9 nano-

10 deca-

Name the first element, then the polyatomic ion. If two elements

are present, name both, then the polyatomic ion. (e.g.; NaHCO3

Is sodium hydrogen carbonate)

It is an Acid (must be aqueous)

Does the acid contain a polyatomic ion?

YES NO

Ending of polyatomic ion

-ate -ite

Name the polyatomic

ion, replacing the –ate

ending with –ic. Add the word acid.

Name the polyatomic

ion, replacing the –ite ending with –ous. Add the word acid.

Write the prefix hydro,

then the name of the

second element with –ic ending. Add the word acid.