Inorganic Nomenclature

common names: historical, but not very revealing chemically
systematic names are much more informative!

Binary Compounds (two elements)
    Three classes:
        I.  Metal + non-metal where metal does not exhibit
            variable oxidation state behavior

            * name cation first, anion second (space between)
            * cation takes the name of the element
            * monatomic anion takes the root of the element
               name followed by -ide

            examples: NaCl = sodium chloride
                              Li₃N = lithium nitride
                              CaS = calcium sulfide
                              Al₂O₃ = aluminum oxide

    II. Metal + non-metal, but metal exhibits variable
        oxidation state behavior.

            * same rules apply as above but
            * cation can have more than one possible charge:

                    Fe²⁺ and Fe³⁺ both exist
                    (remember the Law of Multiple proportions?)

            * must indicate in the name which one we have:
               - use parentheses and a roman numeral to indicate
                  the ox state of the cation, again with spaces.

                    FeCl₂ = iron(II) chloride (ferrous chloride)
                    FeCl₃ = iron(III) chloride (ferric chloride)

                    MnO = manganese(II) oxide
                    MnO₂ = manganese(IV) oxide

        alkali metals (Gp1A)
        alkaline earth metals (Gp2A)
        silver (Ag, always +1)
        aluminum (Al, always +3)
        zinc (Zn, always +2)

        * the first element in the formula is named first,
           using the full element name, space then...
        * the second is named as if it were an anion (-ide)
        * prefixes are used to denote the #'s of each atom
           present:

                mono = 1                hexa = 6
                di = 2                      hepta = 7
                tri = 3                      octa = 8
                tetra = 4                  nona = 9
                penta = 5                deca = 10

        * mono is never used as a prefix for the first element
        * vowels may be dropped from the end of the prefix
           if the element name begins with a vowel

            examples: N₂O₅ = dinitrogen pentoxide
                              P₄O₁₀ = tetraphosphorous decoxide
                              CS₂ = carbon disulfide
                              ClF₃ = chlorine trifluoride

First things first: some element symbols are not related to their current names, but are derived from their original (sometimes Latin) names.
 

Type I:     sodium oxide = Na₂O
                    sodium is always +1, while oxygen is -2
                         atoms must be present in a 2:1 ratio
.
                barium sulfide = BaS
                         barium is +2, S is -2 (see rule 7 for assigning OS)
.
                aluminum bromide = AlBr₃
                    aluminum is +3 and Br is always -1 when bound to a metal

Type II:   iron(II) oxide = FeO
                    oxide is -2 so the cation and anion
                    are 1:1 in the formula
                platinum(IV) chloride = PtCl₄
                vanadium(III) oxide = V₂O₃
                    2 and 3 are the smallest whole numbers
 
Type III:  tetrasulfur tetranitride = S₄N₄
                    sulfur is first in the formula, nitrogen last
                diphosphorous tetrachloride = P₂Cl₄
 
Note: For Type III compounds the formulas may not be empirical!  The compounds are molecular, and hence discrete molecules exist.

Oxyanions: oxygens bonded to a central atom and the whole species bears a negative charge

    The following suffixes apply when only two oxyanions
    of a given element are known:
.
        -ite = fewer oxygens
        -ate = more oxygens
.
    The following prefixes apply when more than two
    oxyanions of a given element are known:
.
        hypo- = fewest oxygens
        per- = most oxygens

    Example:  ClO^- = hypochlorite
                      ClO₂^- = chlorite
                      ClO₃^- = chlorate
                      ClO₄^- = perchlorate
.
                      analagous anions exist for Br and I as well.
.
    What is cesium perchlorate ?          CsClO₄
    *What is Cr(ClO₃)₃?                        chromium(III) chlorate

*polyatomic ions: parenthesis are required in the formula when more than one is present!

NH₄⁺ = ammonium
OH^- = hydroxide
CN^- = cyanide
O₂^2- = peroxide

Polyatomic anions with -2 or -3 charges may be "protonated" by H+ to form hydrogen-containing polyatomic anions hich are less one net negative charge.  -3 ions may also be "doubly protonated" to yield monanions.  These are shown below:
 

    1) monatomic anion: anion does not contain oxygen 
        * Substance must be IN water to be termed an acid.
.
            hydro ---- ic (space) acid
.
    2) oxoanion: the anion name is modified as follows
.
            ate -> ic (space) acid
            ite -> ous (space) acid
.
        * Here the substance need not be dissolved in water to take the acid name, the reason is they all are derived from the reaction of "anhydrides," acidic non-metal oxides, with water:
.
            SO₃          +      H₂O  ---->  H₂SO₄
    sulfur trioxide        water            sulfuric acid
.
            N₂O₅          +      H₂O  ---->  2 HNO₃
dinitrogen pentoxide                      nitric acid
.
    Examples:
.
        HClO₄ = perchloric acid
        hypochlorous acid = HClO
        HF(aq) = hydrofluoric acid
        H₂SO₃ = sulfurous acid
        H₂S(aq) = hydrosulfuric acid
        H₂S (as a gas) = dihydrogen sulfide
        HBr(aq) = hydrobromic acid
        HBr = hydrogen bromide