Magnetic Anisotropy Measurements with Orthogonal Directional SQUID Detection

Alternative Title

Structural and magnetic properties of [M(C₅H₅NO)₆](NO₃)₂ (M = Coᴵᴵ, Cuᴵᴵ)


A superconducting susceptometer with SQUID (superconducting quantum interference device) detectors parallel and perpendicular to the magnetic field has been used to measure single crystal magnetic susceptibility anisotropy. The method allows calculation of the parallel and perpendicular components of an axial susceptibility tensor from a single known orientation of the crystal. The magnetic anisotropy of the nitrate salts of the hexakis(pyridine N-oxide) complexes of cobalt(II) and copper(II) were analyzed with this technique. The complexes crystallize in the space group R3 with the metal atom at the center of the unit cell, which imposes a center of inversion and a threefold rotation axis at the metal atom. The NO3 - anions are positionally disordered with one main and several minor positions. The predominant position (>90%) is orthogonal to the threefold axis, with the nitrogen atom on the unique axis. The [Co(C5H5NO)6]2+ cation has octahedral coordination about the metal environment and the [Cu(C5H5NO)6]2+ ion is slightly distorted from regular octahedral symmetry. The metal-ligand bond lengths are 2.090 (1) and 2.092 (2) Å for the cobalt and copper complexes, respectively. Crystal data are as follows: [Co(C5H5NO)6](NO3)2, space group R3, Z = 1, a = 9.489 (2) Å, α = 83.41 (2)°, R = 5.0%, 1050 reflections; [Cu(C5H5NO)6](NO3)2, space group R̄3, Z = 1, a = 9.504 (3) Å, α = 83.41 (5)°, R = 5.4% for 640 reflections. © 1982 American Chemical Society.



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© 1982 American Chemical Society (ACS), All rights reserved.