Difference Between Calcium Carbonate and Calcium Bicarbonate

The key difference between calcium carbonate and calcium bicarbonate is that the calcium carbonate molecule consists of Ca, C, and O chemical elements whereas calcium bicarbonate consists of Ca, C, O, and H chemical elements.

Calcium carbonate is a carbonate of calcium that has the chemical formula CaCO₃. It occurs naturally and appears as a white solid. On the contrary, Calcium bicarbonate is not a solid, it exists as an aqueous solution only. The chemical formula of this compound is Ca(HCO₃)₂.

CONTENTS

1. Overview and Key Difference
2. What is Calcium Carbonate
3. What is Calcium Bicarbonate
4. Side by Side Comparison – Calcium Carbonate vs Calcium Bicarbonate in Tabular Form
5. Summary

What is Calcium Carbonate?

Calcium carbonate is a carbonate of calcium that has the chemical formula CaCO₃. This compound naturally occurs as limestone, chalk, calcite, etc. Therefore, it is a common substance in rocks. Ex: calcite or aragonite (Limestone contains both these forms). This compound occurs as white hexagonal crystals or powder, and it is odorless.

Moreover, it has a chalky taste. The molar mass of this compound is 100 g/mol and the melting point is 1,339 °C (for the calcite form). However, it has no boiling point because this compound decomposes at high temperatures. We can get this compound by mining the calcium-bearing minerals. But this form is not pure. We can obtain pure form using a pure quarried source such as marble. When calcium carbonate reacts with acids, it forms CO₂ gas. When it reacts with water, it forms calcium hydroxide. In addition, it can undergo thermal decomposition releasing CO₂ gas.

What is Calcium Bicarbonate?

Calcium bicarbonate is carbonate of calcium having the chemical formula Ca(HCO₃)₂. It does not occur as a solid, only exists as an aqueous solution. This solution contains calcium ions (Ca²⁺), bicarbonate ions (HCO₃^–) and CO₃²– along with dissolved carbon dioxide. However, the concentrations of these ions depend on the pH of the medium, which means, different ions predominate at different pH values.

The molar mass of this compound is 162.11 g/mol. This compound forms when rainwater containing dissolved carbon dioxide reacts with limestone. Consequently, this compound washes away with rainwater.

What is the Difference Between Calcium Carbonate and Calcium Bicarbonate?

Calcium carbonate is a carbonate of calcium that has the chemical formula CaCO₃. The molar mass of this compound is 100 g/mol. Moreover, these molecules contain Ca, C, and O chemical elements. Calcium bicarbonate is carbonate of calcium having the chemical formula Ca(HCO₃)₂. The molar mass of this compound is 162.11 g/mol. In addition, these molecules contain Ca, C, O and H chemical elements.

Summary – Calcium Carbonate vs Calcium Bicarbonate

The major carbonate of calcium is calcium carbonate and calcium bicarbonate. The main difference between calcium carbonate and calcium bicarbonate is that the calcium carbonate molecule consists of Ca, C and O chemical elements whereas the calcium bicarbonate consists of Ca, C, O, and H chemical elements.

Reference:

1. “Calcium Carbonate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here 
2. “Calcium Bicarbonate.” Wikipedia, Wikimedia Foundation, 29 June 2018. Available here 

Image Courtesy:

1.’Calcium carbonate rocks’By Ferdous – Own work, (CC BY-SA 3.0) via Commons Wikimedia  
2.’Calcium bicarbonate’By Epop – Own work (Public Domain) via Commons Wikimedia