Phase equilibria studies of the system K2SO4-MnSO4-H2O published revealed discrepancies between the data presented in the literature regarding the solid phases formed at ambient temperatures. The solubility in the system at 298 K and 313 K was determined. At 298 K, the existence of the double salt K2SO4 center dot 3MnSO(4).5H(2)O and of MnSO4 center dot H2O was confirmed. The examinations at 313 K showed the formation of the stable solid phases MnSO4 center dot H2O, K2SO4 center dot 2MnSO(4), K2SO4 center dot MnSO4 center dot 1.5H(2)O, K2SO4 and the formation of a metastable phase K2SO4 center dot MnSO4 center dot 2H(2)O. (C) 2010 Elsevier B.V. All rights reserved.