what is h3o

H3O is the chemical formula for hydronium, which is a cation with a positive charge. It is formed when a water molecule combines with a positively charged hydrogen ion (H+). Hydronium is commonly found in acidic aqueous solutions and is the simplest form of oxonium ions, in which three entities are attached to an oxygen atom, resulting in a net positive charge. The H3O+ molecule has a trigonal pyramidal molecular geometry with the oxygen atom at its apex and is isoelectronic with ammonia. It is found in both diffuse and dense molecular clouds and has a dipole moment due to its symmetry. The concentration of hydronium ions directly relates to pH, which is a measure of the acidity or basicity of a solution