Covalent compounds are formed when two or more atoms share electrons to achieve stability. This sharing allows each atom to fill its outer electron shell, which is essential for chemical stability. Common examples of covalent compounds include water (H₂O) and carbon dioxide (CO₂), where the atoms are held together by strong bonds. These compounds can exist as gases, liquids, or solids, depending on their molecular structure and the forces between them. Covalent compounds often have lower melting and boiling points compared to ionic compounds, making them more versatile in various applications, from cooking to industrial processes.