Geocheminar winter-2013

In many oxide mineral systems, the initial product of precipitation from a fluid is a metastable phase, seemingly violating our understanding of thermodynamics. A possible explanation is that phase stability depends not only on temperature and pressure, but also on particle size due to a surface energy term prominent in nano-sized crystals. Powerful new in situ experimental techniques combined with ab initio calculations have revealed the origin of this excess energy, and how it influences the crystallization of TiO2 during its earliest stages. The results suggest that some minerals may have a much richer history than previously imagined.