Question 2.10: Determining Names and Formulas of Ionic Compounds of Metals ......
Determining Names and Formulas of Ionic Compounds of Metals That Form More Than One Ion
Problem Give the systematic name for the formula or the formula for the name:
(a) Tin(II) fluoride (b) CrI_3 (c) Ferric oxide (d) CoS
Solution (a) Tin(II) ion is Sn^{2+}; fluoride is F^-. Two F^- ions balance one Sn^{2+} ion:
tin(II) fluoride is SnF_2. (The common name is stannous fluoride.)
(b) The anion is I^−, iodide, and the formula shows three I^−. Therefore, the cation must be Cr^{3+}, chromium(III) ion: CrI_3 is chromium(III) iodide. (The common name is chromic iodide.)
(c) Ferric is the common name for iron(III) ion, Fe^{3+}; oxide ion is O^{2−}. To balance the charges, the formula is Fe_2O_3. [The systematic name is iron(III) oxide.]
(d) The anion is sulfide, S^{2−}, which requires that the cation be Co^{2+}. The name is cobalt(II) sulfide.