Ionic bond
Electrostatic attraction between oppositely charged ions.
Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities. It is the primary interaction occurring in ionic compounds and is one of the main types of bonding, along with covalent bonding and metallic bonding. Ionic bonds result from the transfer of electrons from a metal to a non-metal to obtain a full valence shell for both atoms, forming cations and anions.
- type
- Chemical bonding
- key_components
- Cations and anions
- primary_interaction
- Electrostatic attraction
- typical_compounds
- Ionic compounds (e.g., salts)
- conductivity
- Conducts electricity when molten or in solution
Lore & Background
Ionic bonding can result from a redox reaction when atoms of an element (usually metal), whose ionization energy is low, give some of their electrons to achieve a stable electron configuration, forming cations. An atom of another element (usually nonmetal) with greater electron affinity accepts one or more electrons to attain a stable electron configuration, becoming an anion. The electrostatic attraction between the anions and cations leads to the formation of a solid with a crystallographic lattice in which the ions are stacked in an alternating fashion. In such a lattice, it is usually not possible to distinguish discrete molecular units, so the compounds formed are not molecular. However, the ions themselves can be complex and form molecular ions like the acetate anion or the ammonium cation.
Reader's Guide
Ionic bonding is significant because it explains the formation and properties of a vast class of compounds, including common table salt (sodium chloride). Ionic compounds generally have high melting points, depending on the charge of the ions; the higher the charges, the stronger the cohesive forces and the higher the melting point. They tend to be soluble in water, though stronger cohesive forces lower solubility. Ionic compounds conduct electricity when molten or in solution, but typically not when solid. The lattice energy of a solid crystalline ionic compound can be determined experimentally using the Born–Haber cycle or predicted using the Born–Landé equation. Ionic bonding will occur only if the overall energy change for the reaction is favorable; in general, the reaction is exothermic, though some formations, such as mercuric oxide, are endothermic. The charge of the resulting ions is a major factor in bond strength, with higher charges leading to stronger electrostatic forces.
Did You Know?
- Ionic bonding is one of the main types of bonding, along with covalent bonding and metallic bonding.
- Clean ionic bonding—in which one atom or molecule completely transfers an electron to another—cannot exist; all ionic compounds have some degree of covalent bonding or electron sharing.
- Ionic compounds conduct electricity when molten or in solution, typically not when solid.
- The electrostatic potential in an ionic crystal can be expressed using the Madelung constant, which accounts for the geometry of the crystal.
Frequently Asked Questions
What is Ionic bond and how does it work?
Ionic bond is a type of chemical bonding driven by the electrostatic pull between ions carrying opposite charges. It typically forms when a metal atom hands off one or more electrons to a non-metal atom, so both end up with a complete outer electron shell.
What are Ionic bond's key components?
The two essential players in any ionic bond are cations (positively charged ions) and anions (negatively charged ions). Their mutual electrostatic attraction is what holds the ionic compound together.
What role does Ionic bond play in compounds?
Ionic bond is the primary force holding together ionic compounds such as common table salts. It sits alongside covalent and metallic bonding as one of the three major bonding types in chemistry.
Why does Ionic bond conduct electricity only when molten or dissolved?
In a solid ionic lattice the ions are locked in fixed positions, so charge cannot flow freely. Once the compound melts or dissolves in water, the ions become mobile and are free to carry an electric current.
How is Ionic bond different from covalent bonding?
While covalent bonding shares electrons between atoms, ionic bonding involves a full transfer of electrons from one atom to another. This transfer creates discrete charged ions rather than a shared electron pair.
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