diatomic molecules explained with examples
Diatomic Molecules Explained with Examples
A covalent bond is a chemical bond that arises due to sharing of electrons between atoms. Diatomic molecules are usually formed by covalent bonding. This Buzzle write-up uses various examples of diatomic molecules to give you a better understanding of the concept.
- Homonuclear diatomic molecules
- Heteronuclear diatomic molecules
- In Hydrogen: Hydrogen has one electron in its orbit. The atomic orbitals of two hydrogen atoms overlap so that their atomic orbital is complete, giving rise to a stable H2 molecule.
- In Chlorine: Chlorine has seven electrons in its outermost orbit, and it needs one electron to complete its octet. The atomic orbitals of two chlorine atoms overlap so that their octet is complete, giving rise to a stable Cl2 molecule.
- In Nitrogen: Nitrogen has five electrons in its outermost orbit, and it needs three electrons to complete its octet. It does so by forming three bonds with another nitrogen atom (three electrons are shared in the overlapping orbital).
- In Oxygen: Oxygen has six electrons in its outermost orbit, and it needs two electrons to complete its octet. It does so by forming two bonds with another oxygen atom (two electrons are shared in the overlapping orbital).
- Phosphorus on pyrolysis (heating to very high temperature) gives diatomic phosphorus. Phosphorus exists in a tetraatomic state. On heating, this tetraatomic molecule cracks to give diatomic molecules.
- Lithium usually exists as dilithium in its vapor phase; approximately 1% of gaseous lithium is in the form of Li2.
- Sulfur exists in the S8 state, and when heated to above 720°C, it breaks down to give S2.
- In HCl: This is a diatomic molecule in which the hydrogen atom and the chlorine atom are bonded by a covalent bond. Here, chlorine is more electronegative than hydrogen. Due to this, the electrons are pulled towards the chlorine atom, creating a dipole. The bond length of the H-Cl bond is 0.127 nm.
- In CO: Carbon has 4 electrons in its outermost atomic orbital, whereas oxygen has six electrons in its outermost atomic orbital. In this diatomic molecule, the carbon atom and the oxygen atom are bonded by two covalent bonds and one dative or coordinate bond (oxygen provides a lone pair of electrons to form the dative bond) so that their octet is complete. The bond length of each C-O bond is 0.112 nm.
- In NO*: Nitrogen has 5 electrons in its outermost atomic orbital, whereas oxygen has six electrons in its outermost atomic orbital. In this molecule, the nitrogen and oxygen atom are bonded by two covalent bonds. One of the electrons of the nitrogen that usually takes part in a chemical reaction remains unpaired. This forms a highly reactive chemical compound that is called a radical. Here, the bond length of the N-O bond is 0.115 nm.
- In CN*: Carbon has four electrons in its outermost orbital, and nitrogen has 5 electrons. In this molecule, the nitrogen and carbon atoms are bonded by three covalent bonds. One of the bonding electrons of carbon remain unpaired to form a radical.