Determination of the Distributions of the Spin-Hamiltonian Parameters in Spin Triangles: A Combined Magnetic Susceptometry and Electron Paramagnetic Resonance Spectroscopic Study of the Highly Symmetric [Cr 3 O(PhCOO) 6 (py) 3 ](ClO 4 )·0.5py.

Magnetic susceptibility and X-band electron paramagnetic resonance (EPR) studies have been carried out on the highly symmetric [Cr3 O(PhCOO)6 (py)3 ](ClO4 )·0.5py (1; py = pyridine), whose cation exhibits a D3 h crystallographically imposed molecular symmetry. While magnetic susceptibility data can be interpreted with an equilateral magnetic model described by the effective multispin Hamiltonian Ĥ = -2 J(Ŝ1 ·Ŝ2 + Ŝ2 ·Ŝ3 + Ŝ3 ·Ŝ1 ), EPR data require an isosceles model described by the multispin Hamiltonian Ĥ = -2 J( Ŝ1 · Ŝ2 + Ŝ2 · Ŝ3 ) - 2 J' Ŝ3 · Ŝ1 , where Δ J = J - J' ≠ 0. Moreover, EPR data reveal the interplay of antisymmetric exchange (or Dzyaloshinskii-Moriya) interactions, described by a 2G(Ŝ1 × Ŝ2 + Ŝ2 × Ŝ3 + Ŝ3 × Ŝ1 ) term, which induce significant anisotropy to the ST = 1 /2 ground state of 1, as well as an important broadening of the g⊥ resonance ( g strain). Through careful analysis of these data and in conjunction with neutron scattering data, this g strain can be deconvoluted into distributions of the individual spin-Hamiltonian parameters Δ J and |G|. This method of analysis provides simultaneous estimates of the central values and distribution profiles of the spin-Hamiltonian parameters, which are shown not to be described by monodisperse values.