Problem 1.8: Calcium carbonate CaCO contains both ionic and
From Chapter 1 Problem Set. Level 3: System Integration.
Question
Calcium carbonate (CaCO₃) contains both ionic and covalent bonds within the same compound. Identify which bonds are ionic and which are covalent, and explain why this combination produces a crystal lattice that is difficult to pull apart.
Answer
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Covalent bonds: the three C–O bonds within the carbonate ion (CO₃²⁻), forming a rigid, symmetric internal framework. Ionic bond: the electrostatic attraction between Ca²⁺ and CO₃²⁻. The rigid covalent unit does not deform, and the strong ionic attraction locks these units into a dense, interlocking crystal lattice - exceptionally stable and difficult to dissolve.