Ionic Bonding (Part III)

Slightly More Complex Ionic Compounds

Compounds in which two or more ions are held together by electrical attraction.

The positive ions are called cations.The negative ions are called anions. In an ionic compound, the total charge

of the cations is in perfect balance with the total charge of the anions.

What are Ionic Compounds?

Up until this point, the cation had only one possible charge: Group 1A cations such as Li+, Na+, or Cs+, can only have a charge of +1. Similarly, Group 3A cations like B3+ and Al3+ can only have a charge of +3.

For slightly more complex ionic compounds, the cation can have a charge that is different depending on the compound and on the conditions under which it is prepared.

As an example, iron (Fe) can have a cationic charge of +2 or +3. Copper (Cu) can have a cationic charge of +1 or +2.

Slightly More Complex Ionic Compounds

Both the Simple and Slightly More Complex Ions Are Combined in One Table

Oxidation Numbers of Monatomic Ions

1+ 2+ 3+ 4+

cesium, Cs+

copper (I), Cu+

gold (I), Au+

hydrogen, H+

lithium, Li+

potassium, K+

silver, Ag+

sodium, Na+

barium, Ba2+

beryllium, Be2+

cadmium, Cd2+

calcium, Ca2+

cobalt (II), Co2+

copper (II), Cu2+

iron (II), Fe2+

chromium (II), Cr2+

lead (II), Pb2+

magnesium, Mg2+

mercury (II), Hg2+

nickel (II), Ni2+

platinum (II), Pt2+

tin (II), Sn2+

zinc, Zn2+

manganese (II), Mn2+

aluminum, Al3+

bismuth (III), Bi3+

boron, B3+

cobalt (III), Co3+

gold (III), Au3+

iron (III), Fe3+

antimony (III), Sb3+

chromium (III), Cr3+

lead (IV), Pb4+

platinum (IV), Pt4+

silicon, Si4+

tin (IV), Sn4+

titanium (IV), Ti4+

5+

niobium (V), Nb5+

vanadium (V), V5+

1- 2- 3- 4-

bromide, Br-

chloride, Cl-fluoride, F-

iodide, I-

oxide, O2-

sulfide, S2-

nitride, N3-

phosphide, P3-

carbide, C4-

silicide, Si4-

Example: Iron reacts with oxygen to form a product containing iron (III).

The Roman Numeral III means that the charge of the cation is +3.

In the table iron (III) is Fe3+; Oxygen will become the oxide ion, O2-.

Using one of the charge balancing methods, one gets Fe2O3 as the correct answer.

How to Use the Table of Oxidation States of Monatomic Ions (Explicit)

Example: Lead reacts with oxygen to form a product.

In the table, lead is present as both lead (II), Pb2+, or lead (IV), Pb4+; Oxygen will become the oxide ion, O2-.

Using Pb2+ and one of the charge balancing methods, one gets PbO as the correct answer.

Using Pb4+ and one of the charge balancing methods, one gets PbO2 as the correct answer.

Either answer would be acceptable.

How to Use the Table of Oxidation States of Monatomic Ions (Not

Explicit)

If the formula is AuCl3, what is the charge of the gold cation in the compound?The chloride anion is Cl-. Three Cl- can only be balanced by Au3+. Therefore, the gold cation in AuCl3 must be gold (III), Au3+.

Given the Formula, Find the Charge of the Cation (Example 1)

If the formula is SnS, what is the charge of the tin cation in the compound?

The sulfide anion is S2-. S2- can only be balanced by Sn2+. Therefore, the tin cation in SnS must be tin (II), Sn2+.

Given the Formula, Find the Charge of the Cation (Example 2)

Simple ionic compounds have two word names.

The first word is the element name of the cation.

The second word is the name of the anion, which is derived from the element name with an –ide ending.

Example: NaCl is sodium chloride

Rules for Naming SimpleIonic Compounds (Review)

The first word is the element name of the cation with the associated Roman numeral in parentheses. An example would be iron (II).

This is read as “iron two.” Remember that the Roman numeral is the

charge of the cation, not the subscript of the cation in the chemical formula.

The second word is the name of the anion name as for simple ionic compounds.

Example: FeCl2 is named iron (II) chloride.

Rules for Naming Slightly More Complex Ionic Compounds

PtF4

CrI2Cu2O

Co2S3

Naming Examples

• Platinum (IV) fluoride

• Chromium (II) iodide

• Copper (I) oxide

• Cobalt (III) sulfide

Both the Simple and Slightly More Complex Ions Are Combined in One Table

Oxidation Numbers of Monatomic Ions

1+ 2+ 3+ 4+

cesium, Cs+

copper (I), Cu+

gold (I), Au+

hydrogen, H+

lithium, Li+

potassium, K+

silver, Ag+

sodium, Na+

barium, Ba2+

beryllium, Be2+

cadmium, Cd2+

calcium, Ca2+

cobalt (II), Co2+

copper (II), Cu2+

iron (II), Fe2+

chromium (II), Cr2+

lead (II), Pb2+

magnesium, Mg2+

mercury (II), Hg2+

nickel (II), Ni2+

platinum (II), Pt2+

tin (II), Sn2+

zinc, Zn2+

manganese (II), Mn2+

aluminum, Al3+

bismuth (III), Bi3+

boron, B3+

cobalt (III), Co3+

gold (III), Au3+

iron (III), Fe3+

antimony (III), Sb3+

chromium (III), Cr3+

lead (IV), Pb4+

platinum (IV), Pt4+

silicon, Si4+

tin (IV), Sn4+

titanium (IV), Ti4+

5+

niobium (V), Nb5+

vanadium (V), V5+

1- 2- 3- 4-

bromide, Br-

chloride, Cl-fluoride, F-

iodide, I-

oxide, O2-

sulfide, S2-

nitride, N3-

phosphide, P3-

carbide, C4-

silicide, Si4-