What is the Difference Between Bicarbonate and Carbonate

The main difference between bicarbonate and carbonate is that bicarbonate carries a -1 charge while carbonate carries a -2 charge.

Bicarbonate and carbonate are two important chemical compounds, each with their distinct composition and properties. Understanding their differences and applications is crucial in chemistry and various fields where these compounds play a significant role.

Key Areas Covered

1. What is Bicarbonate
      – Definition, Features 
2. What is Carbonate
      – Definition, Features 
3. Similarities Between Bicarbonate and Carbonate
      – Outline of Common Features
4. Difference Between Bicarbonate and Carbonate
      – Comparison of Key Differences
5. FAQ: Bicarbonate and Carbonate
      – Frequently Asked Questions

Key Terms

Bicarbonate, Carbonate

Difference Between Bicarbonate and Carbonate - Comparison Summary

What are Bicarbonates

Bicarbonate is an anion (negatively charged ion) with the chemical formula HCO3-. It consists of one carbon atom (C), one hydrogen atom (H), and three oxygen atoms (O) covalently bonded together. The arrangement of these atoms forms a linear structure, with the hydrogen atom bonded to one of the oxygen atoms. The bicarbonate ion carries a net charge of -1 due to the presence of the extra electron.

The bicarbonate ion is part of a family of chemical species that also includes the carbonate ion (CO32-) and the carbon dioxide molecule (CO2). These species are closely related and often interconvertible in various chemical reactions. Understanding the chemistry of bicarbonate involves recognizing its role in maintaining pH balance in solutions, particularly in biological systems. One of the primary roles of bicarbonate in both biological and environmental contexts is its involvement in pH regulation. Bicarbonate is crucial in maintaining the pH balance within a narrow range in living organisms.

Compare Bicarbonate and Carbonate

In the bloodstream, bicarbonate acts as a buffer system in which it can accept and release protons (H+ ions) to help regulate the blood’s pH. This buffering capacity is vital for maintaining the body’s internal environment within the optimal pH range, which is approximately 7.35 to 7.45 for human blood. Deviations from this range can have severe consequences for biological processes and health.

The following reversible chemical reaction can represent the bicarbonate buffering system:

HCO3– + H+ ⇌ H2O + CO2

In this equation, the bicarbonate ion (HCO3-) can act as a base by accepting a proton (H+), which results in the formation of water (H2O) and carbon dioxide (CO2). Conversely, in an acidic environment, bicarbonate can release a proton to help neutralize excess acidity.

Applications of Bicarbonate

Bicarbonate, known for its versatile properties and chemical reactivity, finds application in various industries. Notable uses of bicarbonate include its role in baking, where sodium bicarbonate acts as a leavening agent to create a light and fluffy texture in baked goods. It’s also utilized as an antacid to alleviate heartburn and indigestion by neutralizing excess stomach acid. In firefighting, bicarbonate-based dry chemical agents in some fire extinguishers help suppress flames by disrupting the fire triangle. Baking soda serves as a mild abrasive and deodorizer in household cleaning tasks, from surface cleaning to unclogging drains. Moreover, sodium bicarbonate aids in food preservation, maintaining vegetable color and texture during cooking. In the medical field, it is used to treat metabolic acidosis and support kidney disorders and plays a role in balancing pH during hemodialysis. Bicarbonate’s wide-ranging applications demonstrate its significance across numerous sectors.

What are Carbonates

Carbonate is a polyatomic anion with the chemical formula CO32-. It consists of one carbon atom (C) bonded to three oxygen atoms (O) in a trigonal planar arrangement. The carbonate ion carries a net charge of -2 due to the presence of two extra electrons, resulting in its overall negative charge.

The carbonate ion is closely related to other chemical species, including bicarbonate (HCO3-) and carbon dioxide (CO2). These compounds are interconnected through various chemical reactions and equilibria. Understanding carbonate chemistry is fundamental for grasping its diverse applications. Carbonate compounds, such as calcium carbonate, exhibit versatility in various domains.Bicarbonate vs Carbonate

Notable applications span across construction and architecture, where it fortifies cement and concrete for stability, to agriculture, where it amends soil acidity and enhances crop yield. In water treatment, calcium carbonate regulates pH and controls water hardness, preventing scale buildup. The paper industry benefits from precipitated and ground calcium carbonate as fillers and coatings to improve paper quality. Additionally, calcium carbonate serves as a dietary supplement for essential calcium intake and as an antacid in pharmaceuticals for acid relief. In environmental remediation efforts, it plays a role in neutralizing acidic waste and restoring natural ecosystems. Carbonate’s broad range of uses underscores its significance across industries.

Similarities Between Carbonate and Bicarbonate

  • Carbonate and bicarbonate contain carbon and oxygen atoms in their chemical formulas.
  • Both carbonate and bicarbonate contain the carbonate ion (CO32-).
  • Both ions carry a negative charge.

Difference Between Bicarbonate and Carbonate


Bicarbonate has the chemical formula HCO3-. It consists of one carbon atom (C), one hydrogen atom (H), and three oxygen atoms (O). Carbonate has the chemical formula CO32-. It consists of one carbon atom (C) bonded to three oxygen atoms (O).


Bicarbonate carries a -1 charge, while carbonate carries a -2 charge.

Acid vs Base

Moreover, bicarbonate is amphoteric, which means it can act as a weak acid or a weak base, depending on the circumstances. Carbonate is a weak base and can accept protons (H+) in aqueous solutions to act as a base.


Bicarbonate ions are commonly found in biological systems, including the human body, where they play a role in maintaining blood pH. However, carbonate ions are often found in geological formations such as limestone and marble.

FAQ: Bicarbonate and Carbonate

What are the examples of carbonate and bicarbonate?

Examples of carbonates include calcium carbonate (CaCO₃), found in geological formations like limestone and chalk, and sodium carbonate (Na₂CO₃), also known as soda ash or washing soda. Examples of bicarbonates include sodium bicarbonate (NaHCO₃), commonly referred to as baking soda, used in various culinary and household applications, and ammonium bicarbonate (NH₄HCO₃), which serves as a leavening agent in baking and is employed in food production.

Which is stronger, carbonate or bicarbonate?

Bicarbonate is weaker in terms of basicity compared to carbonate. Carbonate has a double negative charge, making it a stronger base than bicarbonate, which has a single negative charge.

What is the test to differentiate bicarbonate and carbonate?

To differentiate between bicarbonate and carbonate ions, you can perform the MgSO4 test. When a carbonate salt reacts with MgSO4, a white salt precipitates. In the case of a bicarbonate salt, not only does a white salt precipitate, but there is also a noticeable brisk effervescence or the release of gas bubbles.


Bicarbonate has the chemical formula HCO3while carbonate has the chemical formula CO32-.The main difference between bicarbonate and carbonate is that bicarbonate carries a -1 charge while carbonate carries a -2 charge.


1. “Carbonate.” Wikipedia. Wikipedia Foundation.
2. “Sodium Bicarbonate.” WebMD.

Image Courtesy:

1. “Carbonate-ion-localised-2D” By Ben Mills – Own work (Public Domain) via Commons Wikimedia
2. “Bicarbonate-resonance” By Hellbus – Own work (CC BY-SA 3.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

Leave a Reply