“…When assuming CN6, K The coordination environment of different cations is complex. Na + cations have been reported with a mean CN in the range of 4-6 (Greaves, 1981;Greaves et al, 1981;Vessal et al, 1992;HoudeWalter et al, 1993;Cormack and Du, 2001;Du and Cormack, 2004;Bernasconi et al, 2012;Kreski et al, 2012) in silicate glass, but also lower (Dubiel et al, 1997) or higher (McKeown et al, 1985;George and Stebbins, 1996;Weigel et al, 2008) values have been mentioned, depending on compositional changes. K + cations have been reported to most likely have a CN of 8-10 (Jackson et al, 1987;Cormier et al, 2010;Kreski et al, 2012), but here as well, 4-6 have also been reported (Greaves et al, 1991;Kamijo et al, 1996), again depending on composition.…”