zwitterioonilised

Zwitterioonilised refers to chemical compounds that contain both a positive and a negative formal charge on different atoms within the same molecule. These molecules are electrically neutral overall, but possess distinct charged regions. The term "zwitterion" is derived from German and means "hybrid ion."

The most common examples of zwitterions are amino acids. In a typical amino acid, the amino group (-NH2) is protonated to become positively charged (-NH3+), while the carboxyl group (-COOH) is deprotonated to become negatively charged (-COO-). This internal charge separation occurs because the molecule can act as both an acid and a base, a property known as amphoterism.

The presence of both positive and negative charges within a zwitterion significantly influences its physical and chemical properties. Zwitterions are generally soluble in polar solvents like water due to their charged nature, and less soluble in nonpolar solvents. Their melting points are typically high, often decomposing before melting, because the electrostatic attractions between oppositely charged ions in the crystal lattice are strong. The pH at which a zwitterion is electrically neutral is called its isoelectric point.