Synthesis and Magnetic Properties of the KCu(IO(3))(3) Compound with [CuO(5)](∞) Chains

[Image: see text] The new quaternary iodate KCu(IO(3))(3) has been prepared by hydrothermal synthesis. KCu(IO(3))(3) crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 9.8143(4) Å, b = 8.2265(4) Å, c = 10.8584(5) Å, β = 91.077(2)°, and z = 4. The crystals are light blue and translucent. There are three main building units making up the crystal structure: [KO(10)] irregular polyhedra, [CuO(6)] distorted octahedra, and [IO(3)] trigonal pyramids. The Jahn–Teller elongated [CuO(6)] octahedra connect to each other via corner sharing to form [CuO(5)](∞) zigzag chains along [010]; the other building blocks separate these chains. The Raman modes can be divided into four groups; the lower two groups into mainly lattice modes involving K and Cu displacements and the upper two groups into mainly bending and stretching modes of [IO(3)E], where E represents a lone pair of electron. At low temperatures, the magnetic susceptibility is characterized by a broad maximum centered at ∼5.4 K, characteristic for antiferromagnetic short-range ordering. Long-range magnetic ordering at T(C) = 1.32 K is clearly evidenced by a sharp anomaly in the heat capacity. The magnetic susceptibility can be very well described by a spin S = 1/2 antiferromagnetic Heisenberg chain with a nearest-neighbor spin exchange of ∼8.9 K.