“…When the lone pair is inert in a nine-coordinate environment, the geometry is largely TRPS-9 (Lobo et al, 2019;Mahmoudi et al, 2019), SAPRS-9 (Deng et al, 2013;Farina et al, 2013;Hayati et al, 2018;Imran et al, 2015;Kowalik et al, 2017;Lobo et al, 2019;Mahmoudi et al, 2019;Morsali & Mahjoub, 2004;Najafi et al, 2018;Song et al, 2014;Zhao et al, 2007) and CUS-9 (Farina et al, 2013;Né meth et al, 2015;Yang et al, 2019) (Table S6). For one selected example, the authors (Morsali & Mahjoub, 2004) argue for a void around the ninecoordinate Pb II atom so that the lone pair should be active.…”