Abstract. Experimental results are reported on S-state ions incorporated into PbFC 1-type tetragonal single crystals. The spin Hamiltonian parameters of these ions are determined and correlated with structural and physico-chemical properties of the studied compounds. The experimental bi spin Hamiltonian parameters vary linearly with the lattice constant a of the host unit cell. Further, the dependence of the spin Hamiltonian parameters on temperature has been investigated and parametrised. The results of a Raman investigation of the hosts are presented
