The partial structure factors in Figs. 4b and 5b help identify the contribution to the first S(Q) peak as having Be-F, Be-Li, and Be-Be components. Using the partial structure factor results from simulations, we can evaluate the charge alternation peaks described by Sharma et al. The second peak at 2.7 Å -1 appears to contain the charge alternations that are predicted to have positive correlations with matching cation-cation and anion-anion pairs and negative correlations with opposite pairs. This peak is composed of positive F-F and Be-Be correlations along with negative F-Be correlations. Note that the negative Li scattering length causes the F-Li and Be-Li correlation to be opposite of the expected sign in the neutron structure factor.