A chemical bond is the phenomenon of chemical species like atoms held together by electrostatic or electronic forces. Of the several types of chemical bonds, a special type exists in the molecule of boron hydride BH3 which exists as a dimer B2H6 molecule. It contains two types of hydrogen atoms. Four hydrogen atoms are of one type, which are used in making four normal covalent bonds with two boron atoms. The remaining two H atoms form bridges between the two boron atoms through three-centre electron-pair bonds. This type of bond involves three atoms but only two electrons. Since the shape of the electron cloud resembles a banana, it is called a banana bond.