An ionic bond is a type of chemical bond that’s formed when electrons are transferred from one atom to another. This means one atom becomes positively charged while the other is negatively charged, creating an electrostatic attraction between the anions and cations.
Continue reading to learn more about how ionic bonds form, their characteristics, and some common examples. We’ll also consider the differences between ionic and covalent bonds.
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What are chemical bonds?
Chemical bonds refer to the electrostatic attraction between atoms of different elements, which can combine to form a crystal or molecular compound.
Chemical bonding only involves the outermost electrons, otherwise known as valence electrons. It generally follows the octet rule, which is when atoms bond with other atoms to have eight electrons in their valence shell.
There are four main types of chemical bonds, which are classified based on how the electrons are distributed or arranged:
- Covalent bonding – electrons are shared equally by the constituent atoms. Covalent bonds can either be polar or nonpolar, depending on the angles between the constituent atoms.
- Ionic bonding – the valence electrons are transferred to one of the atoms, resulting in oppositely charged ions. Ionic bonds are the strongest type of chemical bonds.
- Metallic bonding – this involves the attraction between the positively charged ions and the surrounding freely-moving electrons.
- Hydrogen bonding – this is a relatively weak type of bonding between hydrogen and oxygen. The hydrogen develops a partial positive charge, making it a type of polar covalent bond.

Basics of ionic bonding
Ionic bonding occurs between a metal element, typically alkali metals and alkaline earth metals, and nonmetals (particularly halogens) with different electronegativity values.
They generally take the form of a crystalline solid or salt, which is formed from the neutralisation reaction between an acid and a base. Ionic compounds usually have crystalline lattice structures with repeating patterns.
How do ionic bonds form?
Ionic bonds are formed when a metallic atom donates its valence electrons to a non-metallic atom. This results in strong electrostatic attraction between the two ions, which requires more energy to break compared to other types of bonds.
Characteristics & properties of ionic bonds
Ionic bonds are a type of atomic bond based on the strong electrostatic attraction between cations and anions. One atom becomes a donor of electrons while the other atom becomes the acceptor. Ionic bonds typically produce crystalline solid structures with very high melting points.
Ionic compounds have similar physical and chemical properties. The majority take the form of solid crystals, which makes them brittle. They also tend to have very high melting and boiling points. The common table salt, for example, has a melting point of 801 °C – that’s even higher than lead!
Ionic compounds tend to have higher enthalpies of fusion and vaporisation, which means they require more energy compared to molecular compounds.
Another defining characteristic is that they conduct electricity well when they’re dissolved in water. Ionic compounds are also excellent heat insulators when solid.
Examples of ionic bonds
All compounds with ionic bonds are salts. They generally take the form of crystalline solids when they’re at room temperature, and they dissolve in water. There are various types of salts – some are neutral, while others are acidic or basic. You can read more about the different types of salts and their uses here.
Common ionic compounds in daily life
The most common ionic compound in daily life is table salt, or sodium chloride, which can be derived from seawater or mined as rock salt. Table salt has many culinary applications, including seasoning and preserving food.

Another ionic compound that’s often found in the kitchen is sodium bicarbonate, also called baking soda or bicarbonate of soda. As the name suggests, it’s often used in baking because it helps the dough rise by releasing carbon dioxide. Sodium bicarbonate is also used in fire extinguishers.
Industrial applications of ionic compounds
One of the most commonly used ionic compounds in industry is sodium hydroxide, otherwise known as caustic soda. It’s a strong alkaline compound that’s used in the manufacture of soaps, detergents, de-clogging agents and paper.
Sodium hypochlorite is another example of an ionic compound with important industrial applications, including the synthesis of pharmaceutical products and large-scale water treatment. It’s also used to bleach paper and textiles on an industrial scale. You can read more about the uses of sodium hypochlorite here.
Comparing ionic and covalent bonds
There are some interesting differences between ionic and covalent bonds, which can have a significant impact on the structure and properties of their respective compounds.
Key differences
Ionic bonds are imbalanced in terms of their distribution of valence electrons. Only one atom has all the valence electrons, making it negatively charged.
Covalent bonds, however, share electrons almost equally. As a result, they don’t conduct electricity when dissolved in water (unlike ionic compounds, which are good electrical conductors in water).
Impact on compound properties
A compound’s chemical bond doesn’t just affect its ability to conduct electricity; it influences its melting and boiling points too.
Covalent compounds, for instance, have much lower melting and boiling points than ionic compounds. Ionic bonds are also stronger than covalent bonds, although the latter still provides stability and complexity to large organic molecules
Ionic bonds in nature and technology
In nature, ionic chemical bonds exist as inorganic salts. They play key roles in regulating the weather and climate, such as in the case of dissolved salt in the oceans. As we explain below, ionic bonds also have important technological applications.
Importance of bonds in biology
Chemical bonds have crucial functions in biology and human physiology. Amino acids, for example, form covalent bonds to make polymers of proteins.
Meanwhile, the weak hydrogen bonds in DNA make it easy for the DNA to replicate. The ionic bonds of salts are also vital in cellular structure and nutrient transport.
Technological applications
Some ionic compounds are used in power storage, such as in the case of lithium batteries. They’re also crucial in synthesising and designing polymers, acting as crosslinks between the polymer chains. This is what helps make puncture-resistant materials so tough.
Conclusion
An ionic bond is the strongest type of chemical bond. It involves the transfer of electrons from one atom to another, which creates electrically charged ions. Ionic bonds typically produce simple salts with very high melting points. Some common examples of ionic bonds in daily life include table salt and sodium bicarbonate.