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 Lone Pair?

By Angie Bates
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.

A lone pair references a pair of electrons in the valence shell of an atom which are not bonded to another atom or molecule. Since only those electrons in the valence, or outer, shell of an atom participate in bonding, lone pairs are studied in chemistry to account for the different shapes of molecules with the same number of bonds. Since electrons repel each other, molecules that have central atoms with a lone pair will be shaped differently than those that do not.

Electrons orbit the nucleus of an atom in various shells. Each shell can hold a certain number of atoms, and electrons always orbit in pairs, spinning in opposite directions. The electrons in the outer shell of the atom, called the valence shell, may be shared with other atoms in order to form bonds and create molecules. In some molecules, all the valence shell electrons in the central atom are bonded to another atom, but in others only some are bonded. A pair of electrons in an atom that are not bonded to another atom is called a lone pair.

In chemistry, loan pairs are studied because they affect the way certain molecules are shaped, which in turn may affect how the molecules behave. Explained by the valence shell electron pair repulsion (VSEPR) theory, electrons naturally repel one another, which accounts for the shapes of various molecules. For example, beryllium chloride (BrCl2) consists of a beryllium atom bonded to two chlorine atoms. Each chlorine atom is attached to the beryllium atom by a pair of beryllium's electrons through covalent bonding. Since no unbonded electrons remain in the valence shell, the farthest apart the electrons holding the chlorine atoms can move from each other is 180°, creating a linear molecule.

Tin chloride (SnCl2), however, does have a loan pair of electrons. Just like beryllium chloride, tin chloride has two chlorine atoms bonded to a tin atom by electron pairs. Unlike beryllium chloride, tin chloride has an additional unbonded pair of electrons, a lone pair, in the valence shell as well. This results in the tin chloride molecule having a bent shape as all three electron pairs try to move a maximum distance from each other.

The resulting angle between the chloride atoms should then be 120°. Scientific research has discovered it is actually 95°, however. This discrepancy is a result of the loan pair's orbital. The orbital of a loan pair is greater than the orbital of a bonded pair, which leads to the angle between atoms being smaller.

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.