Ions that contain more than one element in them. 

Example: OH^- (Hydroxide)

 AB + C --> A + CB

Example: Zn(OH)₂ + 2 Na --> Zn (s) + 2 NaOH

AB+CD --> AD+CD

Example: AgNO₃ + HCl --> AgCl (s) + HNO₃

AB + C --> A (s) + CB or AB + C --> A + CB (s)

or, AB + CD --> AD + BC (s) or AB + CD --> AD (s) + BC

Example: 3 NaOH + Al --> 3 Na + Al(OH)3 (s)

C_xH_y + O₂ --> CO₂ + H₂O + energy

Example:  CH₄ + 2O₂ --> CO2 + 2H₂O + energy

acid⁺ + base^- --> salt + water

Example:  H₂SO₄ + 2 NaOH --> Na₂SO₄ + 2H₂O