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Figure 7
(a) Time-dependent diffraction data (2θ versus t) collected from the 2 mm borosilicate capillary flow cell during the crystallization of an aqueous 30 g/100 g Na2SO4 solution under heating–cooling cycles, highlighting the water peak corresponding to the solution phase followed by the rapid appearance of the 021 and 131 diffraction peaks after crystallization. (b) The same data as (a) in a contour-plot format for clarity. (c) Time-dependent Raman spectra collected during the same crystallization experiment centred on the 980 cm−1 peak corresponding to the solvated Na2SO4 species and the appearance of the spectral feature centred around 989 cm−1 corresponding to the Na2SO4·10H2O mirabilite phase. (d) Peak heights of the 980 and 989 cm−1 fingerprint peaks highlighted in (c), showing their respective time dependencies, the time of crystallization Tcryst, the solution saturation temperature Tsat and the metastable zone width (MSZW): not to be confused with the induction time as this is a polythermal experiment not an isothermal experiment. |