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ionic and molecular compounds

aming Molecular Compounds

Molecular compounds consist of nonmetallic elements that share electrons through covalent bonds. The type of molecular compounds we will focus on naming in this lesson are binary molecular compounds. Binary molecular compounds consist of two nonmetal elements. For example, a water molecule (H2O) is a binary molecular compound consisting of the nonmetals hydrogen and oxygen.

To name a binary molecular compound, the first element is given its elemental name, and the second element is given its root (i.e. carb-, hydr-, ox-, fluor-) with the suffix “-ide.” For example:

● HF = hydrogen fluoride

Greek prefixes are used for molecular compounds to account for the number of each element in the compound. See Table 1 for the Greek prefixes that represent the numbers 1 – 10.

Table 1. Greek prefixes. Number of Atoms Prefix

1 Mono- 2 Di- 3 Tri- 4 Tetra- 5 Penta- 6 Hexa- 7 Hepta- 8 Octa- 9 Nona-

10 Deca-

For example:

● CO2 = carbon dioxide

● N2O3 = dinitrogen trioxide

The prefix “mono-” is never used for the first element, and only used for the second element if ambiguity exists in the naming. A few examples for using the prefix “mono-” on the second element are:

● carbon monoxide

● dinitrogen monoxide

● nitrogen monoxide