If the compound is ionic, then the name of the cation (usually metal) comes first, followed by the 'compound' name of the anion. To find the compound name of an anion, replace the end of the element's name with 'ide'. name of cation + name of anion, suffix 'ide'
E.g. NaCl: sodium, the cation, first, followed by chlorine changed with the suffix 'ide' = sodium chloride If the anion is polyatomic and contains oxygen, then the suffix is 'ate'. name of cation + name of polyatomic oxygen anion, suffix 'ate' E.g. Na2CO3: sodium, the cation, first, followed by a polyatomic group containing carbon and oxygen to form carbonate = sodium carbonate Note:
E.g. MgO: magnesium, the cation, first, followed by oxygen changed with the suffix 'ide' because oxygen is the sole ion and not part of a polyatomic group = magnesium oxide Sometimes if the compound contains hydrogen, the word 'hydrogen' shortens to 'bi' such as with NaHCO3, which is known as sodium hydrogen carbonate or sodium bicarbonate. Hydrogen compounds
If the compound contains hydrogen and a metal, the metal comes first, followed by the word 'hydride', to denote the hydrogen component. metal + hydride
E.g. NaH: sodium, the metal, first, followed by hydrogen changed with the suffix 'ide' = sodium hydride If the compound contains hydrogen and a non-metal and does not contain water (H2O), then the hydrogen comes first, followed by the element's name replaced with the 'ide' suffix. hydrogen + non-metal, suffix 'ide'
E.g. HF: hydrogen first, followed by fluorine changed with the suffix 'ide' = hydrogen fluoride If the hydrogen non-metal compound dissolves in water, it starts with the 'hydro' prefix, followed by the element's name replaced with an 'ic' suffix, followed by 'acid'. hydro(name of element, suffix 'ic') acid
E.g. HCl: hydro, then chlorine with an 'ic' suffix, then 'acid' = hydrochloric acid Oxygen compounds
When naming ionic compounds that contain oxygen the basic rule is similar. If the compound contains hydrogen and an oxygen anion (oxyanion) and does not contain water, then hydrogen comes first, followed by the element name with the suffix 'ate'. hydrogen + element, suffix 'ate'
E.g. HCO3: hydrogen followed by carbon with the suffix 'ate' = hydrogen carbonate The 'ate' rule is used for the most common or the only compound made with an oxyanion. Some compounds, however, form more than one type of compound with oxygen and the amount of oxygen will affect the prefixes and suffixes used. This occurs for all oxyanions, with or without hydrogen involved. Table 1.1: Naming more than one type of oxygen compound
Oxygen level| Prefix| Element| Suffix|
A little oxygen| hypo-| | -ite|
Some oxygen| | | -ite|
More oxygen| | | -ate|
A lot of oxygen| per-| | -ate|
E.g. Chlorine forms four different oxyanions named:
ClO = hypochlorite
ClO2 = chlorite
ClO3 = chlorate
ClO4 = perchlorate
The oxygen level corresponds with the relative amounts in different compounds and not necessarily the specific numbers of oxygen atoms. If an element forms just two types of oxyanion compounds, then the suffixes 'ite' and 'ate' will suffice. If the hydrogen oxyanion compound is dissolved in water, it forms an acid using similar rules, only the 'ite' suffix changes to 'ous' and the 'ate' suffix changes to 'ic', followed by the word 'acid'. Table 1.2: Naming more than one type of hydrogen oxyanion acid Oxygen level| Prefix| Element| Suffix| Acid|
A little oxygen| hypo-| | -ous| |
Some oxygen| | | -ous| |
More oxygen| | | -ic| |
A lot of oxygen| per-| | -ic| |
E.g. The above example with chlorine and oxygen plus hydrogen:...