“…The bridging fluorines are connecting three yttrium atoms F(3Y), while in LiYF 4 [29] and aNaYF 4 [38], all the fluorine atoms are shared between two [YF 8 5À ]. In the case of KY 3 F 10 , the two kinds of fluorines are reported with a ratio 1:3, one connecting two yttrium, F(2Y) and one three yttrium F(3Y) [33]. The corresponding 19 F chemical shifts values measured are different: À56, À67 and À59 ppm for F(3Y) in YF 3 and KY 3 F 10 respectively, À108, À82 and À89 ppm for F(2Y) in KY 3 F 10 , LiYF 4 and aNaYF 4 , respectively.…”