Magnetic Spongelike Behavior of 3D Ferrimagnetic {[Mn^II(imH)]₂[Nb^IV(CN)₈]}_<i>n</i> with <i>T</i>_c = 62 K

Fully reversible room temperature dehydration of 3D {MnII2(imH)2(H2O)4[NbIV(CN)8]·4H2O}n (1; imH = imidazole) of Tc = 25 K results in the formation of 3D ferrimagnet {[MnII(imH)]2[NbIV(CN)8]}n (2), with Tc = 62 K, the highest ever known for octacyanometalate-based compounds. The dramatic magnetostructural modifications in 2 provide the first example of magnetic spongelike behavior in an octacyanometallate-based assembly.