What color is Iron (Fe) when dissolved in water?

When iron (Fe) is dissolved in water, particularly in the form of ferrous ions (Fe²⁺), it often imparts a reddish-brown color to the solution due to the formation of iron hydroxides and other compounds that can precipitate under certain conditions. The reddish-brown coloration is most commonly observed when iron is oxidized or in its ferric state (Fe³⁺), which can create a visible hue in the water.

This color arises because of light absorption properties of the iron compounds formed in water, which interact with light to reflect specific wavelengths, resulting in the characteristic reddish-brown appearance. Understanding this characteristic is crucial for water treatment operators to identify and manage water quality issues related to iron in the supply.