Iron does react with mercury to form an amalgam. In fact, iron is one of the few metals that reacts with mercury at room temperature to form an amalgam. The amalgam is a silvery-white, pasty substance that is composed of iron and mercury atoms.

The reaction between iron and mercury is a redox reaction, in which iron atoms are oxidized and mercury atoms are reduced:

```

Fe(s) + Hg(l) -> FeHg(l)

```

The oxidation of iron atoms occurs first, resulting in the formation of Fe2+ ions:

```

Fe(s) -> Fe2+(aq) + 2e-

```

The electrons released by the oxidation of iron atoms are then transferred to mercury atoms, resulting in the formation of Hg2+ ions:

```

Hg(l) + 2e- -> Hg2+(aq)

```

The Fe2+ and Hg2+ ions then combine to form the iron-mercury amalgam:

```

Fe2+(aq) + Hg2+(aq) -> FeHg(l)

```

The iron-mercury amalgam is a stable compound that is resistant to further chemical reactions. This is why mercury is often used to coat iron surfaces to protect them from corrosion.