Various inorganic phosphorus species in prebiotic Earth and extraterrestrial settings

Phosphorus (P) is a critical element for life, yet its primary geochemical form—orthophosphate—is poorly soluble and unreactive under early Earth conditions, presenting the longstanding “phosphate problem” in prebiotic chemistry. In this brief review, we give an overview of various prebiotic P sources from geochemical viewpoint. We then also discuss the feasibility of reactive P-N species in aqueous ammoniacal solutions on the early Earth. This review article also suggests the formation of inorganic P-N species in aqueous solutions. Reduced phosphorus compounds, such as phosphite produced by schreibersite corrosion and other terrestrial processes, as well as condensed phosphates and phosphites like trimetaphosphate and pyrophosphite, can react with aqueous ammonia under anoxic (or even oxic) conditions to yield amidophosphates and amidophosphites. These P–N species are more soluble, highly reactive toward organic substrates, and capable of driving phosphorylation under mild environmental conditions. Serving early Earth as an example, we further explore the potential for similar chemistry beyond Earth, particularly in ammonia-bearing aqueous environments on Mars, Enceladus, and other ocean worlds where reduced phosphorus and hydrothermal systems may coexist. We also briefly discuss the recent findings of various P species in asteroids Ryugu and Bennu. We further suggest that P–N chemistry could represent a widely accessible route to organophosphorus compounds, with important implications for the emergence of life in diverse habitable settings.