Refinement of the crystal structure of potassium hexaaquairon(II) sulfate, K2[Fe(H2O)6](SO4)2 and potassium hexaaquazinc(II) sulfate, K2[Zn(H2O)6](SO4)2 - Euler Harald; Barbier Bruno; Meents Alke; Kirfel Armin (Zeitschrift für Kristallographie - New Crystal Structures, 2009)