The ground-state electronic structures of K 3 V(ox) 3 3 3H 2 O, Na 3 V(ox) 3 3 5H 2 O, and NaMgAl 1-x V x (ox) 3 3 9H 2 O (0 < x e 1, ox = C 2 O 4 2-) have been studied by Fourier-transform electronic absorption and inelastic neutron scattering spectroscopies. High-resolution absorption spectra of the 3 Γ(t 2g 2 ) f 1 Γ(t 2g 2 ) spin-forbidden electronic origins and inelastic neutron scattering measurements of the pseudo-octahedral [V(ox) 3 ] 3-complex anion below 30 K exhibit both axial and rhombic components to the zero-field-splittings (ZFSs). Analysis of the ground-state ZFS using the conventional S = 1 spin Hamiltonian reveals that the axial ZFS component changes sign from positive values for K 3 V(ox) 3 3 3H 2 O (D ≈ +5.3 cm -1 ) and Na 3 V(ox) 3 3 5H 2 O (D ≈ +7.2 cm -1 ) to negative values for NaMgAl 1-x -V x (ox) 3 3 9H 2 O (D ≈ -9.8 cm -1 for x = 0.013, and D ≈ -12.7 cm -1 for x = 1) with an additional rhombic component, |E|, that varies between ∼0.8 and ∼2 cm -1 . On the basis of existing crystallographic data, this phenomenon can be identified as due to variations in the axial and rhombic ligand fields resulting from outer-sphere H-bonding between crystalline water molecules and the oxalate ligands. Spectroscopic evidence of a crystallographic phase change is also observed for K 3 V(ox) 3 3 3Y 2 O (Y = H or D) with three distinct lattice sites below 30 K, each with a unique ground-state electronic structure.