elektronipuudus

Elektronipuudus, also known as electron deficiency, is a concept in chemistry referring to an atom, molecule, or chemical species that has fewer electrons than is required to achieve a stable electron configuration, typically a full valence shell. This deficiency often makes the species highly reactive and prone to accepting electrons from other substances.

In organic chemistry, electron-deficient centers are often found in electrophiles. These are species that are attracted to regions of high electron density. Common examples include carbocations, which are positively charged carbon atoms with a vacant p orbital, and molecules containing electronegative atoms that withdraw electron density, such as carbonyl compounds. The carbon atom in a carbonyl group (C=O) is electron-deficient due to the high electronegativity of oxygen, making it susceptible to nucleophilic attack.

In inorganic chemistry, electron deficiency is a key characteristic of Lewis acids. Lewis acids are defined as electron pair acceptors. Boron trifluoride (BF3) is a classic example; the boron atom has only six valence electrons and can accept an electron pair from a Lewis base to form a coordinate covalent bond. This drive to complete its octet makes BF3 a strong Lewis acid.

The concept of electron deficiency is crucial for understanding chemical reactivity, reaction mechanisms, and the formation of chemical bonds. Species with electron deficiency play vital roles in a wide range of chemical reactions, from nucleophilic addition to acid-base chemistry.