2.2 Nomenclature

Nomenclature of Inorganic Compounds

Classification of Chemical Compounds

  • Organic Compounds: Contain carbon.

  • Inorganic Compounds: Composed of elements other than carbon.

Ionic Compounds

  • Definition: Composed of cations (positive ions) and anions (negative ions).

  • Ionic Characteristics:

    • Cations: Typically metals; carry a positive charge.

    • Anions: Typically nonmetals; carry a negative charge.

Ionic Charges

  • Common ionic charges include:

    • +1: Li+, Na+, K+, H+, Ag+

    • +2: Mg2+, Ca2+, Zn2+, Sr2+, Ba2+

    • +3: Al3+; variable charge for transition metals such as Fe2+/Fe3+, Cu+/Cu2+, etc.

    • -1: F-, Cl-, Br-, I-

    • -2: O2-, S2-, Se2-, CO32-

    • -3: N3-, P3-

Common Cations and Their Charges

  • Group IA Cations (+1):

    • Hydrogen (H+), Lithium (Li+), Sodium (Na+), Potassium (K+), etc.

  • Group IIA Cations (+2):

    • Magnesium (Mg2+), Calcium (Ca2+), Strontium (Sr2+), etc.

  • Group IIIA Cations (+3):

    • Aluminum (Al3+), Gallium (Ga3+)

  • Transition Metals: Commonly have variable charges (e.g., Fe2+/Fe3+, Cu+/Cu2+).

Common Anions and Their Charges

  • 1- Anions:

    • Fluoride (F-), Chloride (Cl-), Bromide (Br-)

  • 2- Anions:

    • Oxide (O2-), Sulfide (S2-), Carbonate (CO32-)

  • 3- Anions:

    • Nitride (N3-), Phosphate (PO43-)

Formation of Compounds

  • Need for simplification:

    • E.g., Mg+2 + O-2 simplifies to MgO (not Mg2O2).

Types of Inorganic Compounds

  • Categories:

    • Binary Oxides

    • Hydrides

    • Halide Salts

    • Ternary Oxyacids

    • Hydroxides

    • Oxyacids

Ionic Compounds with Monoatomic Ions

Noted basic reactions:

  • Combining metal ions with oxygen ions to form binary compounds:

    • Na+ + O2- → Na2O (Sodium Oxide)

    • Al3+ + O2- → Al2O3 (Aluminum Oxide)

Nomenclature of Oxides

  • Format: Metal + Oxide

    • Example: CaO (Calcium Oxide)

Ionic Compounds with Polyatomic Ions

Hydroxide Ions

  • Structure: Metal ion + Hydroxide ion (-1)

    • Example: Na+ + OH- → NaOH (Sodium Hydroxide)

Nomenclature of Oxyacids

  • Format: Hydrogen ion + Non-Metal + Oxygen

    • Example: H2SO4 (Sulfuric Acid)

  • Naming Convention: Oxyacid naming involves the suffix –ic for polyanions ending in –ate, and –ous for polyanions ending in –ite.

Summary of Inorganic Compound Types

  • Oxides: Metal ion + oxygen ion

  • Hydrides: Metal ion + hydrogen ion

  • Halides: Metal ion + non-metal

  • Hydracids: Hydrogen ion + non-metal ion

  • Anhydrides: Non-metal ion + oxygen ion

  • Hydroxides: Metal ion + hydroxide