"electron pair." YourDictionary, n.d. Web. 21 October 2018. <http://www.yourdictionary.com/electron-pair>.
electron pair. (n.d.). Retrieved October 21st, 2018, from http://www.yourdictionary.com/electron-pair
(plural electron pairs)
(chemistry, physics) Two electrons having opposite spin but all other quantum numbers the same; i.e two electrons in the same atomic orbital or molecular orbital, especially such electrons that function in concert to form a covalent bond
English Wiktionary. Available under CC-BY-SA license.