Write the formula for the polyatomic ion and name each of the following compounds:
d. Fe(HCO₃)₃

Verified step by step guidance

1. Step 1: Identify the polyatomic ion in the compound. The formula HCO₃⁻ represents the bicarbonate ion, which is a polyatomic ion composed of hydrogen, carbon, and oxygen.
2. Step 2: Recognize the metal cation in the compound. The formula Fe represents iron, which can have multiple oxidation states. In this case, the compound contains Fe³⁺ because it is paired with three bicarbonate ions (HCO₃⁻).
3. Step 3: Determine the name of the polyatomic ion. The name of HCO₃⁻ is bicarbonate (or hydrogen carbonate).
4. Step 4: Combine the name of the metal cation with its oxidation state in Roman numerals and the name of the polyatomic ion. Since the iron cation has a +3 charge, its name is iron(III).
5. Step 5: Write the full name of the compound. The name of Fe(HCO₃)₃ is iron(III) bicarbonate.

Key Concepts

Polyatomic Ions

Polyatomic ions are ions composed of two or more atoms covalently bonded together, which carry a net charge. They are essential in understanding chemical formulas and naming compounds, as they often represent complex groups of atoms that behave as a single unit in chemical reactions. Examples include carbonate (CO₃²⁻) and bicarbonate (HCO₃⁻).

Iron (Fe) Oxidation States

Iron can exhibit multiple oxidation states, commonly +2 and +3, which are crucial for determining the correct formula and name of iron-containing compounds. In the compound Fe(HCO₃)₃, iron is in the +3 oxidation state, indicating that it is bonded to three bicarbonate ions, each contributing a -1 charge, balancing the overall charge of the compound.

Nomenclature of Ionic Compounds

The nomenclature of ionic compounds involves naming the cation (positive ion) followed by the anion (negative ion). For compounds containing polyatomic ions, the name of the polyatomic ion is used directly. In the case of Fe(HCO₃)₃, the compound is named iron(III) bicarbonate, reflecting the iron's oxidation state and the presence of the bicarbonate ion.