Abstract
Phosphorus is a minor element that controls the formation of several key planetary minerals. It is also an element critical to the development of life. A common assumption of phosphorus chemistry is that at low temperatures, phosphorus would have been a volatile component of ices or gases in the outer Solar System. Here I propose that phosphorus was depleted as a volatile throughout the developing solar system, and as a result, volatile forms of phosphorus would have been minimal, even in the cold regions of the solar nebula. Based on thermodynamic equilibrium models and metal phosphidation kinetics coupled to a simple 1D gas diffusion model, phosphorus migrated rapidly to the inner Solar System, forming solids such as phosphides and phosphates, and removing volatile phosphorus across large portions of the Solar System.