37220-42-1

Mobile, yellow liquid.Evolves carbon monoxide on exposure to air or light. Soluble in nickel tetracarbonyl and most organic solvents; soluble with decomposition in acids and alkalies; insoluble in water.

Flammable, dangerous fire risk. Toxic by ingestion, inhalation, and skin absorption.

Although nickel carbonyl can be obtained from nickel and carbon monoxide at atmospheric pressure and moderate temperature, the production of iron pentacarbonyl requires a pressure of 5– 30 MPa, a temperature of 150–200 C, and the presence of reactive iron. Even at high temperature and pressure, massive iron reacts sluggishly with carbon monoxide, so iron sponge, with its greater surface area, is used as starting material.

Iron pentacarbonyl is an easily combustible substance. It does not react with water or with weak or dilute acids. With concentrated acids, the corresponding iron salts are formed with the evolution of carbon monoxide and hydrogen. Reactions with halogens yield iron halides. Iron pentacarbonyl also reduces organic compounds; for example, nitrobenzene is reduced to aniline; ketones to alcohols; and indigo to indigo white.

The trigonal bipyramidal structure has been preferred to the square pyramidal one in the interpretation of electron diffraction, Raman and infrared and thermodynamic data; the apparently contradictory dipole moment of 0-8 D being attributed to atom polarization. A single crystal X-ray structure determination at - 80°C has confirmed the trigonal bipyramidalstructure.