Understanding Binary Covalent Compound Nomenclature
Naming binary covalent compounds using prefixes follows specific rules that help chemists communicate clearly about molecular structures. When two nonmetals combine to form a compound, we use numerical prefixes to indicate how many atoms of each element are present in the molecule.
Definition: Binary covalent compounds are molecules formed between two different nonmetal elements that share electrons to create chemical bonds.
The prefix system uses specific terms to denote quantity: mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), hepta- (7), octa- (8), nona- (9), and deca- (10). When naming these compounds, the first element keeps its full name while the second element gets an -ide ending. The prefix mono- is typically omitted for the first element.
Example:
- CO₂ = carbon dioxide (one carbon, two oxygen)
- N₂O = dinitrogen monoxide (two nitrogen, one oxygen)
- SO₃ = sulfur trioxide (one sulfur, three oxygen)
- CCl₄ = carbon tetrachloride (one carbon, four chlorine)











