Naming Binary Ionic Compounds—With and Without Transition Metals
The first question you ask yourself “Is there a transition metal?”
If there are NO TRANSITION METALS:
Name to Formula
 List the cation 1st, anion 2nd.
o Make sure that when writing name to formula, the oxidation numbers of the
formula add up to ZERO.
 You do this by using the CRISS CROSS method.
 Write the oxidation number for each element.
 Transfer the superscript oxidation number from the cation to the
subscript position in the anion.
 Do the same with the anion’s oxidation number.
 After CRISS CROSSING, ignore the sign on the subscript
o If you were going to write in a 1, you just leave the 1 invisible
o The numbers DO matter in this case because the specific formula is important.
Ex:
Sodium Sulfide
Potassium chloride

= Na+1 S-2
= Na+1 S-2
= K+1 Cl-1
= Na2 S
= K+1 Cl-1
= KCl
Remember, the 1’s disappeared because we never put a one in the
subscript.
If there ARE TRANSITION METALS:
Name to Formula
 List the cation 1st, anion 2nd.
o Make sure that when writing name to formula, the oxidation numbers of the
formula add up to ZERO.
o You do this by using the CRISS CROSS method.
 Write the oxidation number for each element. (The oxidation number of
the transition metal is the roman numeral in parenthesis)
 Transfer the superscript oxidation number from the cation to the
subscript position in the anion.
 Do the same with the anion’s oxidation number.
o After CRISS CROSSING, ignore the sign on the subscript
o If you were going to write in a 1, you just leave the 1 invisible
 The numbers DO matter in this case because the specific formula is important.
Ex:
Zinc (III) Oxide
= Zn+3 O-2
= Zn+3 O-2
= Zn2O3
Copper (II) Oxide = Cu+2 O-2 = Cu+2 O-2 = CuO
 Remember, the 2’s both simplified down to 1’s, and 1’s disappeared
because we never put a one in the subscript.
Name to Formula (NO transition metals)
1. sodium sulfide __________________________________
2. calcium bromide __________________________________
3. gallium chloride __________________________________
4. beryllium oxide _____________________________________
5. potassium nitride _____________________________________
Name to Formula (WITH transition metals)
6. zinc (III) selenide__________________________________
7. silver (II) iodide__________________________________
8. cobalt (II) bromide__________________________________
9. copper (II) oxide __________________________________
10.
copper (III) oxide __________________________________
Name to Formula (WITH transition metals)
11.
aluminum phosphide
Is there a transition metal?______
Write the Formula:_______________________
12.
iron (II) fluoride
Is there a transition metal?______
Write the Formula:_______________________
13.
silver (II) nitride
Is there a transition metal?______
Write the Formula:_______________________
14.
calcium oxide
Is there a transition metal?______
Write the Formula:_______________________
15.
Potassium sulfide
Is there a transition metal?______
Write the Formula:_______________________
If there are NO TRANSITION METALS:
Formula to Name
 List the cation 1st.
o The name of the cation is just the name of the element.
 List the anion 2nd.
o The name of the anion is the name of the element with the ending
taking off and “-ide” added.
 The numbers do not matter at all in this case.
Ex:
K2O = Potassium Oxide
LiF = Lithium Flouride
If there ARE TRANSITION METALS:
Formula to Name
 List the cation 1st.
o The name of the cation is just the name of the element.
o Because the Cation is the transition metal, you need to include the
OXIDATION NUMBER of the cation by putting Roman Numerals in
parenthesis
 Do this by REVERSE CRISS CROSS
 List the anion 2nd.
o The name of the anion is the name of the element with the ending
taking off and “-ide” added.
Ex:
Fe2O3 = Fe2O3
= Fe+3O-2
= Iron (III) Oxide
o The (III) in the parenthesis came from the 3 that was subscript next
to the Oxygen in the formula
TiS
= Ti S
= Ti+2S-2
= Titanium (II) sulfide
o We figured out the oxidation number of Titanium was +2 because Ti
and S were balanced. This meant knowing that S was -2, Ti had to be
+2.
Formula to Name (NO Transition Metals)
16.
K2O __________________________________
17.
NaF ___________________________________
18.
KI _____________________________________
19.
Mg3P2 _____________________________________
20.
Al2Se3 _____________________________________
Formula to Name (WITH Transition Metals)
21.
Ni2O __________________________________
22.
CrCl3 _____________________________________
23.
Cu S ___________________________________
24.
Mn3P2 _____________________________________
25.
Au2Se _____________________________________
Formula to Name (some WITH Transition Metals, some WITHOUT)
26.
Rb3N
Is there a transition metal?______ Name the compound:_______________________
27.
Fe2O3
Is there a transition metal?______ Name the compound:_______________________
28.
CaCl2
Is there a transition metal?______ Name the compound:_______________________
29.
GaBr3
Is there a transition metal?______ Name the compound:_______________________
30.
Ag2O3
Is there a transition metal?______ Name the compound:_______________________