Vicky Silviana的实验室

 An electrolysis cell is a container with two electrodes in it. In order to be effective we need partitioning: carefully hit a test tube at ground to remove its bottom, and add glass wool in it. Here we do reduction so anode is inside, cathode is outside. V2+ is very reducing so use paraffin liquid above solution. In a short period, about a few days, you get purple solution which is the end. Heat this solution with excessive ammonium sulfate and magnesium sulfate (V:(NH4)2:Mg=1:5:4)then cool, then you get purple crystals. Similar procedure however, can't dye alums due to unknown reasons. Probably, different ion radius or wrong temperature? (Cooling also failed and solution freezing is driving me mad) to be continued...

 Alums are compounds with the formula AB(SO4)2.12H2O with A=+1 alkali/ammonium and B=+3 hexaaquo ion. The larger A is, or the smaller B is, the better stability crystal has. Most members are not that stable as Tutton's salts and sometimes only solid solutions and cesium alums are stable. Cubic system, octahedral crystals. They are honest in colors, as aqueous solutions of such a highly charged ion usually undergoes hydrolysis. Known examples: Al: Colorless. Best known, with K and NH4 common and stable. Na also possible but very unstable. Sc: Colorless. Unstable. Ti: Purple? Highly reducing both in solid and solution. V: Blue or green or what? Reducing. My procedure gave nothing but alum with solution. Better make pure compound. Cr: Dark purple, very famous. K mixing with KAl is the most common way with ratio variable. Mn: Red. Extremely unstable as any form except a dilute solution in NH4Al in which it is flesh-like orange. See my blog for more details. Fe: Purple? Co: Greyish-blue...