Inorganic Nomenclature Flowchart

Naming compounds:

#1. How many elements are in the compound?

- if only two, go to #2

- if only three, go to #7

- if four or more, go to #10

#2. Is the first element a metal or a nonmetal?

- if a nonmetal, go to #3

- if a metal, go to #4

#3. For a binary compound made of two nonmetals, use the full name of the first element followed by the stem of the second element plus the ending “ide”. If the formula contains more than one atom of the element, the name of the element is preceded by a Greek prefix.

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

Note: “mono” is only used for emphasis, as in carbon monoxide for CO vs. carbon dioxide for CO2

Ex. PCl5 is phosphorus pentachloride; N2O5 is dinitrogen pentoxide

#4 Does the metal have only one charge (oxidation state) or more than one?

- if the metal only has one oxidation state, go to #5

- if the metal only has more than one oxidation state, go to #6

#5 Because the metal only has one charge, that charge is understood. In naming the compound, give the full name of the elemental metal followed by the stem of the nonmetal plus the ending “ide”.

Ex. NaF is sodium fluoride; Al2O3 is aluminum oxide

#6 Since the metal has more than oxidation state, the charge on the particular cation has to be stated in the name. There are two naming systems - the “common” naming system, which uses the Latin name of the metal; the stock (also known as the IUPAC or Systematic) naming system, which uses a Roman Numeral in parentheses to indicate the charge). Some metals do not have a common Latin origin, so these compounds only use the stock naming system.

In the common naming system, the suffixes “-ous” or “-ic” are used to indicate lower or higher charge. This suffix is added to the stem of the Latin name.

While several metals have a Latin name, only the following need to be learned:

Cu - cuprum Fe - ferrum Sn - stannum Pb - plumbum Au - aurum

We still use the Latin derivation for the following:

Ni- nickel (so “nickelic” is Ni+3 and Ni+2 is “nickelous”); also cobaltic and cobaltous

Ex. CuBr2 is cupric bromide (common name) or copper (II) bromide (stock name)

V2S5 is vanadium (V) sulfide, and it only has one name - the stock name.

#7 Does the cation have two elements or is the anion composed of two elements?

- if the cation contains two elements, go to #8

- if the anion contains two elements, go to #9

#8 The only polyatomic cation of importance is the ammonium ion - NH4+.

Ex. NH4I is ammonium iodide; (NH4)3P is ammonium phosphide

#9 Many anions are classified as “oxyanions” because they contain oxygen as well as another element. You have a table of anions & cations that you will need to use. Most oxyanions end in either a “-ate” or “-ite” ending, which means that they are “oxyanions”. Some oxygen-containing anions still end in “-ide”, specifically, OH-1, the “hydroxide” ion. . Not all of the ions are listed, but enough are listed so that you can name ions that are not even listed.

For example, perchlorate (ClO4-1), chlorate(ClO3-1), chlorite (ClO2-1), and hypochlorite (ClO-1) are listed, yet only the iodate ion (IO3-1) is listed. If you wanted the name of IO-, it would be “hypoiodite” since ClO- is “hypochlorite”.

Sometimes sulfur is the second element. The prefix used to indicate sulfur is “thio”. Since CN-1 is the cyanide ion, then SCN-1 is thiocyanide.

Ex. MgSO4 is magnesium sulfate; Sc2(CO3)3 is scandium carbonate; KSCN is potassium thiocyanide.

#10 If the compound has four elements, there are several possibilities.

- if both the cation and the anion have two elements, go to #11.

- if the cation only consists of one element, and the anion contains three elements, go to #12.

- if the compound contains water bonded to the compound, go to #13.

#11 Since the only polyatomic cation of importance is the ammonium ion - NH4+(see #8), this rule combines with rule #9.

Ex. NH4IO2 is ammonium iodite; (NH4)3PO4 is ammonium phosphate.

Some compounds are actually “double salts” which means that they are two compounds combined. For these compounds, name each cation separately, followed by the anion.

Ex. KAl(SO4)2 is potassium aluminum sulfate.

#12 Many oxyanions also contain hydrogen. Some anions can contain only one hydrogen. These anions use the word “hydrogen” in the name, or use the prefix “bi” to indicate the presence of hydrogen. For example, HCO3-1 can be named as either hydrogen carbonate or bicarbonate. If the anion can contain more than one hydrogen (one or two), the name must tell how many hydrogens are present. For example, HPO4-2 is monohydrogen phosphate, while H2PO4-1 is dihydrogen phosphate.

Ex. Fe(H2PO4)3 is ferric dihydrogen phosphate or iron (III). dihydrogen phosphate

#13 Compounds containing water are called “hydrates”. To name a hydrate, following the same rules as above, then add the word “hydrate”, using a prefix to indicate the number of waters.

Ex. CuSO4. 5 H2O is cupric sulfate pentahydrate or copper (II) sulfate pentahydrate