We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is a Lewis Base?

By E.A. Sanker
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

The Lewis theory of acids and bases, named after the chemist G.N. Lewis, seeks to clarify the way two classes of chemicals — acids and bases — interact with one another. A Lewis acid is defined as a substance that accepts a pair of electrons in a chemical reaction, while a Lewis base is a substance that donates a pair of electrons. Although not the most widely taught understanding of acids and bases, the Lewis definitions are broad and useful in studying many different types of reactions.

Chemical compounds are made up of atoms bonded together to form a molecule. Each of these atoms consists of a positively-charged nucleus and a certain number of electrons, which carry a negative charge. The electrons circle the nucleus in a series of orbitals, or different energy levels.

If an atom is deficient in electrons — or, in other words, if it has space in its orbitals to fill — it may attract electrons from another atom, connecting the two substances through a chemical bond in which the electrons are shared. A Lewis base is the compound that donates a pair of electrons in this process. The electrons in a bond are often unevenly shared between two atoms, so the base can effectively "lose" them to the other compound.

The Lewis theory is useful in explaining why certain chemical reactions occur. For example, carbon dioxide (CO2) reacts with water (H2O) to form carbonic acid (H2CO3). One carbon atom bonded to two oxygen atoms makes carbon dioxide, while two hydrogen atoms and one oxygen atom make water.

In the course of the reaction, the water’s oxygen atom donates a pair of electrons to the carbon atom of carbon dioxide, forming a bond between the two molecules. The water is a Lewis base in this situation, since it is the electron donor. Carbon dioxide accepts the electrons into its structure, so it is the Lewis acid.

The above reaction could not be described by the other popular theory of acid and bases, the Bronsted-Lowry model, because it does not involve a proton transfer. The Bronsted-Lowry theory, unlike the Lewis theory, is based on proton donation. In this system, the acid is the compound that donates a positively charged particle, called a proton, while the base is the proton acceptor. While this model is useful in describing many interactions, the Lewis theory is sometimes preferred due to its wider scope.

Lewis bases are classified into different types based on which electron orbital donates the pair of electrons. Often, a Lewis base will be an anion — a substance or compound that carries a negative charge due to an overabundance of electrons. Ammonia is considered a Lewis base, as are water and certain organic compounds.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.