Studies on Salt Hydrate for Latent Heat Storage. I. Crystal Nucleation of Sodium Acetate Trihydrate Catalyzed by Tetrasodium Pyrophosphate Decahydrate

The effect of tetrasodium pyrophosphate decahydrate (Na4P2O7·10H2O) as a nucleation catalyst for sodium acetate trihydrate (CH3CO2Na·3H2O) is shown. The supercooled melt of 10 g of CH3CO2Na·3H2O recrystallized at about 5 degrees below the melting point only when 0.1 g of Na4P2O7·10H2O was added to it. More than a thousand cycles of alternate heating and cooling through the melting point were carried out in this work. Some observations on nucleation are given and the results are discussed on the basis of crystallographic data.