Other challenges of the cyanosulfidic prebiotic synthesis approach is that the reductant, sulfide, has low solubility in water except in alkaline conditions and the main catalyst, copper, has a relatively low abundance in Earth’s crust. To address these problems, an alternative scheme for prebiotic systems chemistry called cyanosulfitic prebiotic synthesis has been proposed. These set of reactions relies on sulfite instead of sulfide, and ferrocyanide to catalyze reactions when exposed to ultraviolet light. The products of these reactions rely on similar chemistry to cyanofidic mechanisms such as reductive homologation and produce similar products such as amino acid precursors as well as sugars and hydroxy acids. Both sulfite (from sulfur dioxide released by volcanos) and ferrous iron (FeII) are hypothesized to have been present in high quantities on the early Earth, suggesting that this is potentially a much for feasible set of reactions.