Sulfate control chemically pure

The complexes of 4-[Co(chxn)3]Cl3 5H20 and (Co(en)3]Cl3 3H20 were prepared by the standard method. The sodium sulfate and the potassium oxalate used were guaranteed reagents of Wako Pure Chemical Industries, Ltd. The Co and NMR spectra were measured with a JEOL GX-270 FT NMR spectrometer operating at 64.1 and 270.1 MHz, respectively. The temperature of the sample solution was controlled at 27iO.S C. The solvents... 

The conditions under which the free water is removed arc as important to proper drying as the physical and chemical properties of the sample. These two factors must be considered simultaneously when designing a drying procedure. Drying by controlling the temperature alone would not be reliable because of the effect the relative humidity (RH) has on the amount of water desorbed from the solid surface. However, drying under controlled conditions of temperature and relative humidity may be effective in free water removal only when a pure calcium sulfate is present. 

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