The main difference between ionic covalent and metallic bonds is their formation; ionic bonds form when one atom provides electrons to another atom whereas covalent bonds form when two atom shares their valence electrons, and metallic bonds form when a variable number of atoms share a variable number of electrons in a metal lattice.
Bonds can be divided into two broad categories; primary bonds and secondary bonds. Primary bonds are the chemical bonds that hold atoms in molecules, whereas secondary bonds are the forces that hold molecules together. There are three types of primary bonds, namely ionic bonds, covalent bonds, and metallic bonds. Secondary bonds include dispersion bonds, dipole bonds, and hydrogen bonds. Primary bonds have relatively high bond energies and are more stable when compared with secondary forces.
Key Areas Covered
1. What are Ionic Bonds
– Definition, Formation, Properties
2. What are Covalent Bonds
– Definition, Formation, Properties
3. What are Metallic Bonds
– Definition, Formation, Properties
4. Difference Between Ionic Covalent and Metallic Bonds
– Comparison of Key Differences
Key Terms
Ionic Bonds, Covalent Bonds, Metallic Bonds
What are Ionic Bonds
Certain atoms tend to donate or receive electrons in order to become more stable by completely occupying their outermost orbit. Atoms with very few electrons in their outermost shell tend to donate the electrons and become positively charged ions, while atoms with more electrons in their outermost orbit have a tendency to receive electrons and become positively charged ions. When these ions are brought together, the attraction forces are occurred due to opposite charges of ions. These forces are called ionic bonds. These stable bonds are also called electrostatic bonds. Solids bonded with ionic bonds have crystalline structures and low electrical conductivity, which is due to a lack of free-moving electrons. 
Bonds usually occur between metal and non-metal that are having a large difference in electronegativity. Examples of ionically bonded materials include LiF, NaCl, BeO, CaF2, etc.
What are Covalent Bonds
Covalent bonds are formed when two atoms share their valence electrons. The two atoms have a small difference in electronegativity. Covalent bonds occur between the same atoms or different types of atoms. For example, fluorine needs one electron to complete its outer shell; thus, one electron is shared by another fluorine atom by making a covalent bond resulting F2 molecule. 
Covalently bonded materials are found in all three states, i.e., solid, liquid, and gas. Examples of covalently bonded materials include hydrogen gas, nitrogen gas, water molecules, diamond, silica, etc.
What are Metallic Bonds
In a metal lattice, valence electrons are loosely attached by the nuclei of metal atoms. Thus, valence electrons require very low energy to release themselves from nuclei. Once these electrons detach, metal atoms become positively charged ions. These positively charged ions are surrounded by a large number of negatively charged, free-moving electrons called an electron cloud. Electrostatic forces are formed due to the attraction between the electron cloud and ions. These forces are called metallic bonds. 
In metallic bonds, almost every atom in the metal lattice shares electrons, so there is no way to determine which atom shares which electron. Because of this reason, electrons in metallic bonds are referred to as delocalized electrons. Due to the free-moving electrons, metals are known as good electricity conductors. Examples of metals with metallic bonds include iron, copper, gold, silver, nickel, etc.
Difference Between Ionic Covalent and Metallic Bonds
Definition
Ionic bonds are electrostatic forces arising between negative and positive ions, while covalent bonds are bonds that occur when two elements share a valence electron in order to get the electron configuration of neutral gasses. Meanwhile, metallic bonds are forces between negatively charged, freely moving electrons and positively charged metal ions.
Bond Energy
The bond energy of ionic and covalent bonds is higher than the bond energy of metallic bonds.
Formation
Ionic bonds form when one atom provides electrons to another atom, while covalent bonds form when two atom shares their valence electrons. Metallic bonds form when a variable number of atoms share a variable number of electrons in a metal lattice.
Conductivity
Ionic bonds have a low conductivity, whereas covalent bonds have a very low conductivity. On the other hand, metallic bonds have very high electrical and thermal conductivity.
Melting and Boiling Points
Ionic bonds have higher melting and boiling points. Covalent bonds have lower melting and boiling points, but metallic bonds have high melting and boiling points.
Physical State
Moreover, ionic bonds only exist in the solid state, while covalent bonds exist in the form of solids, liquids, and gases. Metallic bonds exist in the form of solids only.
Nature of Bond
Ionic bonds are non-directional, but covalent bonds are directional, and metallic bonds are non-directional.
Hardness
Ionic bonds are hard due to their crystalline structure. Covalent bonds are not very hard, with the exception of diamond, silicon, and carbon. Metallic bonds are not very hard.
Malleability
Materials with ionic bonds are not malleable, while materials with covalent bonds are not malleable. However, materials with metallic bonds are malleable.
Ductility
Materials with ionic bonds and covalent bonds are not ductile, but materials with metallic bonds are ductile.
Examples
Examples of ionic bonds include LiF, NaCl, BeO, CaF2, etc., while examples of covalent bonds include hydrogen gas, nitrogen gas, water molecules, diamond, silica, etc. Meanwhile, examples of metallic bonds include iron, gold, nickel, copper, silver, lead, etc.
Leave a Reply