Building and Breaking Bonds by Homogenous Nucleation in Glass-Forming Melts Leading to Transitions in Three Liquid States.

The thermal history of melts leads to three liquid states above the melting temperatures T containing clusters-bound colloids with two opposite values of enthalpy +Δε × ΔH and -Δε × ΔH and zero. All colloid bonds disconnect at T > T and give rise in congruent materials, through a first-order transition at T = T, forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (T) and (T) are separated, T being the temperature of a second order and T the temperature of a first-order phase transition. (T) and (T) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at T gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at T or from T to T. These liquid enthalpies reveal the natural presence of colloid-colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states.