, where 𝑒 ⃗ 𝑖 = 𝑒 ⃗ 𝑖 (𝜗 𝑖 , 𝜑 𝑖 ) is the direction of the local easy axis. Computational limitations direct us toward employing a [Ni7] wheel, with the results multiplied by two to mimic the [Ni14] wheel. The magnetisation data is simulated nicely with J = +4 cm -1 and D(Ni) = -5 cm -1 with the anisotropy axes tilted from the axis of the wheel by θ = 30°, 𝜑 𝑖 = 2𝜋𝑖/7, in agreement with ab initio NEVPT2 calculations (see Figure , blue curves, and below). The magenta curves in Fig. demonstrate for the isotropic case that the substituted [Ni7] model system is close to the original except for low temperatures where the S = 14 ground state cannot be reproduced. The ferromagnetic exchange in 1 is consistent with magneto-structural correlations developed for halide-bridged Ni II dimers where the sign and magnitude of the interaction is dictated by the Ni-Cl-Ni angle -with a switch from antiferromagnetic to ferromagnetic occurring at approximately ≤102° and increasing with decreasing angle. Note the Ni-Cl-Ni angles in 1 are ~82-85°. To further understand the origin and sign of the magnetic coupling constants we have performed DFT calculations on models created from 1 (1A-C, Fig. , Tables ). All seven unique exchange interactions are in the range +1.7 ≤ J ≤ +3.9 cm -1 , consistent with the experimental values. The narrow range of values obtained can be attributed to the presence of similar structural parameters for each metal ion, with the relatively small Ni-µ-O/Cl-Ni angles resulting in ferromagnetic exchange (Table ). To further explore the origin of the sign and magnitude of these interactions we have performed overlap integral calculations between the singly occupied molecular orbitals (SOMOs) of the Ni II ions in a bimetallic model (1D) created from 1 (Fig. ). These calculations suggest competition between one moderate interaction [<Ni(α)dx 2 -y 2 ||Ni(β)dz 2 >] and three weak interactions [<Ni(α)dx 2 - y 2 ||Ni(β)dx 2 -y 2 >; <Ni(α)dz 2 ||Ni(β)dx 2 -y 2 >, <Ni(α)dz 2 ||Ni(β)dz 2 >]. The former contributes to the antiferromagnetic and the latter to the ferromagnetic part of the exchange. In this case, the three weak interactions dominate and the overall result is the observation of a weak ferromagnetic interaction. Spin density analysis suggests a strong spin delocalisation mechanism, with the spin densities on the Ni II ions being between 1.668-1.682. Of the three different bridging moieties, the Cl ion has the largest spin density (0.122 -0.141; Fig. ). To further investigate the contribution from the µ-Cl ion to the total magnetic exchange, we have replaced it with a point charge in model 1D. This results in an antiferromagnetic interaction, changing from +2.3 cm -1 to -6.2 cm -1 , clearly suggesting the major ferromagnetic contribution to the exchange comes from the µ-Cl ion. Bearing in mind the connectivity of next-nearest neighbour Ni II centres through a formate group, we have also estimated the next-nearest neighbour magnetic exchange interaction using model 1E (Fig. ). This is estimated to be very small and ferromagnetic, J = + 0.5 cm -1 . All the Ni II ions in 1 possess slightly distorted octahedral geometries (Table ) and are therefore expected to have axial zero-field splitting parameters of the order D ≤ -10 cm -1 . Ab initio NEVPT2 calculations performed using ORCA 23 reveals values of the D ≤ -6.5 cm -1 , with the major contribution arising from the dxy  dx 2 -y 2 electronic transition (Fig. , Tables ). The D(Ni) axes are oriented approximately along the N(pyrazole)-Ni-O and O(MeOH)-Ni-O vectors, tilted at angles of θ = ~32-37° from the axis of the wheel.