Salt of vitriol, also known as ferrous sulfate, is a chemical compound widely used in various industries and applications. However, there are several synonyms for this term that are also commonly employed. One such synonym is iron(II) sulfate, highlighting the compound's iron content. Another equivalent term is copperas, traditionally referring to the mineral's greenish-blue color. Additionally, it can be referred to as vitriol of Mars due to its association with the red planet. Other synonyms include green vitriol and melanterite, emphasizing the compound's greenish hue. Regardless of the synonym used, salt of vitriol remains a vital ingredient in fertilizers, water treatment, and as a reducing agent in chemical processes.