Question

Supply a Latin system name for each of the following ternary ionic compounds: (a) \(\mathrm{Cu}_{2} \mathrm{SO}_{4}\) (b) \(\mathrm{Fe}_{2}\left(\mathrm{CrO}_{4}\right)_{3}\) (c) \(\mathrm{Hg}_{2}\left(\mathrm{NO}_{2}\right)_{2}\) (d) \(\mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{4}\)

Short answer

(a) Cuprous sulfate, (b) Ferric chromate, (c) Mercurous nitrite, (d) Plumbic acetate.

Step-by-step solution

Identifying the Metal Ion

To determine the Latin system name of each ternary ionic compound, start by identifying the metal in the compound. Look at the chemical formula to determine the element that acts as the cation (positive ion). In (a) it is Cu (copper), in (b) Fe (iron), in (c) Hg (mercury), and in (d) Pb (lead).

Determining the Charge of the Metal Ion

Determine the oxidation state of the metal ion in each compound. (a) In \( \mathrm{Cu}_{2} \mathrm{SO}_{4} \), the sulfate ion \( \mathrm{SO}_{4}^{2-} \) balances with two copper ions, so each copper ion has a +1 charge.(b) In \( \mathrm{Fe}_{2}\left(\mathrm{CrO}_{4}\right)_{3} \), each chromate ion \( \mathrm{CrO}_{4}^{2-} \) requires two Fe ions in total with a +3 charge each.(c) In \( \mathrm{Hg}_{2}\left(\mathrm{NO}_{2}\right)_{2} \), each nitrite ion \( \mathrm{NO}_{2}^{-} \) has a -1 charge, requiring each mercury ion in the diatomic ion \( \mathrm{Hg}_{2}^{2+} \) to have a +1 charge (overall +2 charge spread equally between two atoms).(d) In \( \mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{4} \), each acetate ion \( \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}^{-} \) has a -1 charge, requiring the lead ion to have a +4 charge.

Naming Using Latin Nomenclature

Use the Latin root of the metal's name along with the appropriate suffix depending on the charge.(a) Copper with a +1 charge is called "cuprous," so \( \mathrm{Cu}_{2} \mathrm{SO}_{4} \) is "Cuprous sulfate."(b) Iron with a +3 charge is called "ferric," so \( \mathrm{Fe}_{2}\left(\mathrm{CrO}_{4}\right)_{3} \) is "Ferric chromate."(c) Mercury in \( \mathrm{Hg}_{2}^{2+} \) is called "mercurous," so \( \mathrm{Hg}_{2}\left(\mathrm{NO}_{2}\right)_{2} \) is "Mercurous nitrite."(d) Lead with a +4 charge is called "plumbic," so \( \mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{4} \) is "Plumbic acetate."

Key concepts

Ternary Ionic Compounds

Ternary ionic compounds are fascinating chemical structures composed of three distinct elements. These typically feature a metal bonded to a polyatomic ion, which is a group of atoms that carry a charge overall. In these compounds, the metal commonly acts as the positive ion or cation. The joined polyatomic ions could be such as sulfate \((\mathrm{SO}_4^{2-})\), chromate \((\mathrm{CrO}_4^{2-})\), nitrite \((\mathrm{NO}_2^{-})\), or acetate \((\mathrm{C}_2\mathrm{H}_3\mathrm{O}_2^{-})\).

Understanding ternary ionic compounds requires recognizing the overall neutrality of the compound, which means that the total positive charge from the metal cations balances the total negative charge from the polyatomic anions. This balance is crucial in determining the correct formula and, subsequently, the proper nomenclature for these compounds. For example, in the compound \(\mathrm{Cu}_2\mathrm{SO}_4\), there are two copper ions with a +1 charge each, balancing the -2 charge of the sulfate anion. This interaction ensures the compound's net charge is zero.

Oxidation State Determination

Determining the oxidation state is essential when dealing with ternary ionic compounds. An oxidation state represents the degree of oxidation of an atom in a compound. It’s crucial for accurately naming the compound and understanding its reactivity.

Determining the oxidation state of a metal in a ternary compound involves:

• Identifying the charge of each component, especially the polyatomic ion's known charge.
• Applying the rule that the sum of the oxidation states in a neutral compound equals zero.

For instance, with \(\mathrm{Pb}\left(\mathrm{C}_2\mathrm{H}_3\mathrm{O}_2\right)_4\), you recognize acetate's charge as -1. With four acetate ions, the total negative charge is -4. Therefore, lead must have a +4 charge to balance this, leading to an oxidation state of +4 for lead, or plumbic in Latin nomenclature.

Each metal exhibits variable oxidation states, which significantly influence its chemical properties and interactions. Correctly identifying these states is pivotal in the authentic naming of the compounds.

Latin Nomenclature in Chemistry

Latin nomenclature in chemistry historically derives from the use of Latin or Latinized terms to designate elements' various oxidation states. It offers an alternate and traditional way to name chemical compounds. This system employs roots of the element names with suffixes -"ous" or -"ic," indicating the lower or higher oxidation states, respectively.

Here’s how it works:

• The suffix "-ous" corresponds to the lesser of the oxidation states. For example, in \(\mathrm{Cu}_2\mathrm{SO}_4\), copper exhibits a +1 charge, earning it the name "cuprous" sulfate.
• The suffix "-ic" is used for higher oxidation states. In \(\mathrm{Fe}_2\left(\mathrm{CrO}_4\right)_3\), iron has a +3 charge, and thus the name "ferric" chromate is appropriate.

Understanding Latin nomenclature can deepen your grasp of chemical naming conventions, particularly in historical contexts where this system was more prevalent. It also hones your ability to decipher older chemistry texts and documents that may still employ these traditional names.