Dichlorotetrakis(pyridine)iron(II) is the

coordination complex A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...

with the formula FeCl₂(pyridine)₄. A yellow solid, it is a prominent example of a transition metal pyridine complex. It is used as an anhydrous precursor to other iron complexes and

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

s. According to

X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

, the chloride

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...

s are mutually trans. The complex has a high spin configuration. A monohydrate as well as several related complexes are known, e.g. CoCl₂(pyridine)₄ and NiCl₂(pyridine)₄. It is prepared by treating ferrous chloride with an excess of

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...

References

Iron(II) compounds Iron complexes Chloro complexes Pyridine complexes