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Calcium Carbonate vs. Calcium Bicarbonate: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on December 11, 2023
Calcium carbonate is a stable, solid compound used in supplements and industry, while calcium bicarbonate is a soluble, temporary form often found in water.

Key Differences

Calcium carbonate (CaCO₃) is a stable, solid compound found in rocks and shells. Calcium bicarbonate, on the other hand, is a soluble ionic compound (Ca(HCO₃)₂) that exists only in aqueous solutions.
Calcium carbonate occurs naturally in minerals like limestone and is used in various applications. Calcium bicarbonate forms in water when carbon dioxide reacts with calcium carbonate, typically in natural water bodies.
Calcium carbonate is widely used in dietary supplements, antacids, and industrial applications. Calcium bicarbonate is not used directly but is significant in water hardness and carbonate buffering systems.
Calcium carbonate is less soluble in water and reacts with acids to produce carbon dioxide. Calcium bicarbonate is more soluble and forms when calcium carbonate reacts with carbonic acid in water.
Calcium carbonate is typically found as a white powder or in crystalline forms. Calcium bicarbonate, being in solution, does not have a distinct physical form outside of its aqueous state.

Comparison Chart

Chemical Formula



Stable solid
Exists only in aqueous solutions

Natural Occurrence

In minerals, rocks, shells
In water with dissolved CO₂

Solubility in Water

Poorly soluble
Highly soluble

Common Uses

Supplements, antacids, industry
Involved in water hardness

Calcium Carbonate and Calcium Bicarbonate Definitions

Calcium Carbonate

A white, insoluble, solid compound.
Chalk is primarily composed of calcium carbonate.

Calcium Bicarbonate

Not typically isolated as a solid compound.
In its dissolved form, calcium bicarbonate helps to transport calcium in water.

Calcium Carbonate

Used in various industrial processes.
Calcium carbonate is a primary raw material in cement production.

Calcium Bicarbonate

A soluble calcium salt formed in water.
Calcium bicarbonate contributes to the hardness of water.

Calcium Carbonate

A key component in the formation of limestone and marble.
The White Cliffs of Dover are largely calcium carbonate.

Calcium Bicarbonate

Forms when carbon dioxide reacts with calcium carbonate in water.
Calcium bicarbonate is part of the process in forming stalactites and stalagmites.

Calcium Carbonate

A common ingredient in dietary supplements.
Calcium carbonate is used to prevent or treat calcium deficiencies.

Calcium Bicarbonate

Influences the formation of carbonate rock formations.
The presence of calcium bicarbonate is essential in the geological formation of limestone.

Calcium Carbonate

A base used in antacids.
Calcium carbonate effectively neutralizes stomach acid.

Calcium Bicarbonate

Involved in buffering systems in natural water bodies.
Calcium bicarbonate plays a role in maintaining pH balance in rivers and lakes.


Can calcium bicarbonate be found in solid form?

No, it only exists in aqueous solutions.

What forms when calcium carbonate reacts with acids?

It reacts to produce carbon dioxide gas.

What is calcium bicarbonate used for?

It isn't used directly but affects water hardness and carbonate buffering in water bodies.

Does calcium carbonate occur naturally?

Yes, in minerals like limestone and in animal shells.

How does calcium bicarbonate form?

It forms when carbon dioxide reacts with calcium carbonate in water.

What role does calcium bicarbonate play in water?

It contributes to water hardness and is part of carbonate buffering systems.

Can calcium carbonate be used in food?

Yes, as a calcium supplement and sometimes as a food additive.

What is calcium carbonate used for?

It's used in dietary supplements, antacids, and various industrial applications.

Where is calcium bicarbonate typically found?

In natural water bodies with dissolved carbon dioxide.

Is calcium bicarbonate important for aquatic life?

Yes, it helps maintain the pH and mineral balance in aquatic environments.

Is calcium carbonate soluble in water?

No, it is poorly soluble in water.

Is calcium carbonate safe for consumption?

Yes, it's commonly used in dietary supplements and antacids.

Can calcium carbonate be used as an antacid?

Yes, it's effective in neutralizing stomach acid.

Is calcium carbonate used in construction?

Yes, as a key ingredient in cement and other building materials.

Does calcium carbonate have any role in the environment?

Yes, it's a significant component of marine and terrestrial ecosystems.

How does calcium bicarbonate affect drinking water?

It contributes to the temporary hardness of water.

What is the chemical formula of calcium carbonate?

The formula is CaCO₃.

Is calcium bicarbonate found in tap water?

Yes, especially in areas with limestone geology.

Does calcium bicarbonate influence geological formations?

Yes, it's involved in the formation of limestone and other carbonate rocks.

What is the chemical formula of calcium bicarbonate?

The formula is Ca(HCO₃)₂.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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