Compounds that contain both ionic and covalent bonds are often referred to as "polar covalent compounds" or "polar compounds." These compounds have some degree of both ionic and covalent character due to the unequal sharing of electrons between atoms. Here are a few examples:
Hydrogen Chloride (HCl): In hydrogen chloride, the hydrogen atom donates an electron to the chlorine atom, forming a polar covalent bond. The chlorine atom becomes partially negatively charged, while the hydrogen atom becomes partially positively charged. Although the bond has covalent character, there is a significant electronegativity difference between hydrogen and chlorine, resulting in a partially ionic character.
Ammonia (NH3): Ammonia consists of a nitrogen atom bonded to three hydrogen atoms. The nitrogen atom is more electronegative than hydrogen, causing a partial negative charge on nitrogen and partial positive charges on the hydrogen atoms. This unequal sharing of electrons creates polar covalent bonds.
Water (H2O): Water is a classic example of a compound with both ionic and covalent characteristics. The oxygen atom attracts the shared electrons more strongly than the hydrogen atoms, resulting in partial negative charges on the oxygen atom and partial positive charges on the hydrogen atoms. The polar covalent bonds in water contribute to its unique properties, such as its ability to form hydrogen bonds.
Carbon Dioxide (CO2): Although carbon dioxide is a linear molecule with symmetrical bonds, it still possesses some polarity. Oxygen is more electronegative than carbon, leading to a partial negative charge on each oxygen atom and a partial positive charge on the carbon atom. The polar nature of the carbon-oxygen bonds is responsible for the solubility of carbon dioxide in water.
These examples illustrate compounds that exhibit both ionic and covalent character in their bonding. The degree of ionic or covalent character can vary depending on the electronegativity difference between the atoms involved.