NiCl2·6H2O, also known as nickel(II) chloride hexahydrate, is a chemical compound composed of nickel, chlorine, and water. It appears as greenish-blue crystals and is commonly used in various applications, including electroplating, dyeing, and as a catalyst in chemical reactions. This compound contains six water molecules for each nickel(II) chloride unit, which contributes to its hydration properties. When heated, NiCl2·6H2O can lose its water content, transforming into anhydrous NiCl2. It is important to handle this compound with care, as it can be toxic and harmful if ingested or inhaled.