Vanadium Octacyanoniobate-Based Magnet with a Curie Temperature of 138 K

In this work, we prepared a three-dimensional vanadium octacyanoniobate-based magnet, K_0.10V^II_0.54V^III_1.24[Nb^IV(CN)₈]·(SO₄)_0.45·6.8H₂O. This compound exhibits ferrimagnetism with a Curie temperature of 138 K, in which the sublattice magnetizations of V^II (S = ³/₂) and V^III (S = 1) are antiparallelly ordered to that of Nb^IV (S = ¹/₂). The estimated superexchange interaction constants of V^II−Nb^IV and V^III−Nb^IV are −51 and −25 cm⁻¹, respectively.