To characterize the magnetic properties of Cs 2 NaEuF 6 , we collected field-cooled and zerofield-cooled magnetic susceptibility data from 2 to 395 K at 10 kOe on a 38.1 mg powder sample (Figure ). The compound is a Van Vleck paramagnet, having a temperatureindependent susceptibility at low temperature. The field-cooled and zero-field-cooled data did not deviate from each other. As observed in other Eu 3+ compounds, the data had a Curie tail near the base temperature due to Eu 2+ impurities. Fitting to a Van Vleck model above 55 K gives an energy separation between the 7 F 0 and 7 F 1 levels (λ) of 43.6 meV (λ/k B = 506 K), which agrees with the PL emission spectrum discussed below. The corresponding magnetization curves are linear with no hysteresis, as expected for a paramagnet (Figure ).