Covalent Bonding

Naming Covalent Compounds

Ionic bonds only ever form in one way between two elements (Be and N only ever make Be₃N₂). Ionic compounds don't have to tell us how many of each element are in the formula because Beryllium Nitride only has one combination.

Covalent compounds can have MANY combinations of the same elements. (see pic below) Because of this we have to use prefixes in the name in order to tell everyone how many of each element is in this particular molecule.

Every element in a covalent compound gets a prefix EXCEPT the FIRST element IF there is only ONE.

We do not put the prefix "Mono" at the beginning of the first element.

CO₂ - carbon dioxide (...no "mono" on the first element.)

H₂O - dihydrogen monoxide (..."mono" does go on the second element.)

N₂O₄ - dinitrogen tetraoxide

P₃O₅ - triphosphorus pentoxide

CCl₄ - carbon tetrachloride