Complete understanding of magnetic impurity modes can be obtained from their energies and wavefunctions. Energies are obtained from absorption, Raman, and fluorescent measurements but wavefunction information fromgfactors is most useful when the impurity and hostgfactor are very dissimilar. To this end, impurity modes in MnF2:Co2+have been studied by far ir absorption and Raman scattering, respectively. Thegfactor for thes0mode is measured to be 3.21 and differs substantially from 4.24, the value obtained by EPR in the diamagnetic isomorph MgF2. Thes0energy andgfactor can be explained consistently by exchange mixing of the ground state with excited orbital states of Co2+. Thegfactor for the pair mode at 170.3 cm−1was found to be 1.61, significantly larger thang(s0) ‐g(Mn2+) = 1.2. The Ising pair mode energies andgfactors have been renormalized by including transverse exchange to second order. The correct energies for the impurity modes are obtained but thegfactors of the pair modes do not agree with experiment. Higher‐order spin interactions produced by the orbital motion on the cobalt ion do not significantly alter this result.