Compounds of these metals with nonmetals are named with the same method as compounds in the first category, except the charge of the metal ion is specified by a Roman numeral in parentheses after the name of the metal. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Molecular compounds can form compounds with different ratios of their elements, so prefixes are used to specify the numbers of atoms of each element in a molecule of the compound. It is the least electronegative (most electropositive) ion. You know you have the correct formula for an ionic compound when the positive and negative charges on the ions are the same or "cancel each other out.". For example, consider binary ionic compounds of iron and chlorine. 2.6. Write the formulas of the following ionic compounds: (a) chromium (III) phosphide (b) mercury (II) sulfide (c) manganese (II) phosphate (d) copper (I) oxide (e) chromium (VI) fluoride The name of a binary compound containing monatomic ions consists of the name of the cation (the name of the metal) followed by the name of the anion (the name of the nonmetallic element with its ending replaced by the suffix –ide). Second, charges are not written in a formula. Watch the recordings here on Youtube! The rules for organic compounds, in which carbon is the principle element, will be treated in a later chapter on organic chemistry. 2 → Mg 2+ 2 . Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Write the name of the cation ( + metal) first 2. Sometimes an ionic formula contains compound ions – a group of atoms bonded together with an overall charge. Adjust the subscripts of the cation and anion so the net charge is 0. Legal. If the compound is ionic, does the metal form ions of only one type (fixed charge) or more than one type (variable charge)? This represents the formula SnF2, which is more properly named tin(II) fluoride. First, is the compound ionic or molecular? Name the following ionic compounds, which contain a metal that can have more than one ionic charge: The anions in these compounds have a fixed negative charge (S2−, Se2− , N3−, Cl−, and \(\ce{SO4^2-}\)), and the compounds must be neutral. Keep in mind, hydrogen can go either way, carrying either a positive or negative charge. The other fluoride of tin is SnF4, which was previously called stannic fluoride but is now named tin(IV) fluoride. First, the cation is written before the anion. Other examples are provided in Table \(\PageIndex{3}\). From the answers we derive, we place the compound in an appropriate category and then name it accordingly. Most of the transition metals can form two or more cations with different charges. For more information contact us at or check out our status page at The positive ion, called a cation, is listed first in an ionic compound formula, followed by the negative ion, called an anion. EXAMPLE 2: Magnesium Oxide, MgO, has a typical ionic bond. NaHSO4, sodium hydrogen sulfate 2. Ionic compounds form when positive and negative ions share electrons and form an ionic bond. ThoughtCo uses cookies to provide you with a great user experience. Chemists use nomenclature rules to clearly name compounds. When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms, forming ions. Oxyacids are named by changing the ending of the anion to –ic, and adding “acid;” H2CO3 is carbonic acid. 1. These charges are used in the names of the metal ions: Write the formulas of the following ionic compounds: (a) CrP; (b) HgS; (c) Mn3(PO4)2; (d) Cu2O; (e) CrF6. FeCl3, iron(III) chloride 4. Iron typically exhibits a charge of either 2+ or 3+ (see [link]), and the two corresponding compound formulas are FeCl2 and FeCl3. SO2, sulfur dioxide 3. The formula of an ionic compound can be deduced from the formulae of its ions.