Pigment yellow 42, also known as Yellow Iron oxide is a yellow powder in the form of an alkaline oxide with comparatively stable chemical properties. It is is insoluble in water and alcohol, slightly soluble in acids but completely dissolves in concentrated hydrochloric acid. When heated to 80℃, it loses water and converts to red ferric oxide. It is used in coating, printing ink and paint, and also as a coloring agent for building material, rubber and paper-making. It is widely used due to its bright and pure colour, good weather proofing and high opacity. It is manufactured by the precipitation of ferric oxide hydroxide followed by purification through washing, drying and milling.
