Solutions containing the hydroxide ion attack glass. The reaction initiates via attack of a hydroxide ion at the C5 ester. It is a strong organic base, even stronger than the inorganic hydroxide ion. Numerous mixed ligand complexes of these metals with the hydroxide ion exist. Two solvated electrons combine to form molecular hydrogen and hydroxide ion. Luminol reacts with the hydroxide ion, forming a dianion. The hydroxide ion may act as a base catalyst. The hydroxyl radical, OH, is the neutral form of the hydroxide ion (OH). Asp-123 coordinates to Mg2+ which in turn stabilizes the leaving hydroxide ion. Examples of nucleophiles are hydroxide ion, alkoxides, amines and halides. Fluoride mimics the nucleophilic hydroxide ion in these enzymes' active sites. In aqueous solution the hydroxide ion forms strong hydrogen bonds with water molecules. In terms of charge and size, the fluoride ion resembles the hydroxide ion. In this case the hydroxide ion then forms a complex with the substrate.