Fluoride ions can be chemically inserted into LaSrMnO4 by exposing the compound to F2 gas at elevated temperatures (e.g. 200 °C). Through iodometric titration, Aikens et al. reported that the resulting compounds have a composition of LaSrMnO4F1.7. This indicates that the oxidation state of Mn 3+ in LaSrMnO4 can be increased to nearly Mn 5+ , as it would be expected in LaSrMnO4F1. 7. The authors further demonstrated the formation of LaSrMnO4F, which exhibits alternating occupancy of the interstitial anion layers and a consequent reduction in symmetry from I4/mmm to P4/nmm (Figure ). The formation of LaSrMnO4F is accompanied by an increase in the lattice parameter c from 13.07090(79) Å in LaSrMnO4 to 14.1049(3) Å in LaSrMnO4F. Nowroozi et al