Abstract: | From solutions containing praseodymium perchlorate and periodic acid, three different modifications of [Pr2(ClO4)2(H2I2O10)] · 8 H2O could be obtained. All of them crystallize in the monoclinic system, space group P21/c (α: a = 1091.47(6), b = 728.24(4), c = 1388.84(8) pm, β = 101.420(3)°; β: a = 1169.93(3), b = 728.72(2), c = 1384.50(4) pm, β = 112.303(2)°; γ: a = 1209.56(4), b = 712.53(2), c = 1361.64(5) pm, β = 115.691(1)°). The structures contain Pr3+ cations which are coordinated by [H2I2O10]4— anions yielding two‐dimensional networks. These networks are separated by ClO4— anions yielding a layered structure. |