The structure and thermochemistry of K2CO3─MgCO3 glass

摘要: Carbonate glasses can be formed routinely in the system K2CO3–MgCO3. The enthalpy of formation for one such 0.55K2CO3–0.45MgCO3 glass was determined at 298 K to 115.00 ± 1.21 kJ/mol by drop solution calorimetry molten sodium molybdate (3Na2O·MoO3) 975 K. corresponding heat from oxides −261.12 3.02 kJ/mol. This ternary is shown slightly metastable with respect binary crystalline components (K2CO3 and MgCO3) may further stabilized entropy terms arising cation disorder carbonate group distortions. high degree confirmed 13C MAS NMR measurement average chemical shift tensor values, which show asymmetry anion significantly larger than previously reported values. Molecular dynamics simulations that structure this reflects strong interaction between oxygen atoms distorted anions potassium cations.