KLiSiF₆ and CsLiSiF₆ – A Structure Investigation

Abstract

KLiSiF6 and CsLiSiF6 were synthesized via a high‐pressure/high‐temperature synthesis route. Even though, both substances crystallize in the orthorhombic crystal system with space group Pbcn (no. 60), they show different crystal structures. Main motifs of KLiSiF6 are an [SiF6]2− and an [LiF6]5− unit. In contrast, the main motifs of CsLiSiF6 are an [SiF6]2− and an [LiF5]4− entity. Within both substances, these units are interconnected and form 3‐dimensional networks. The substances were characterized via single‐crystal and powder X‐ray diffraction, as well as infrared spectroscopy and EDX measurements. Additionally, Mn4+‐doped KLiSiF6 was analyzed by means of luminescence spectroscopy. It displays line emission in the red spectral region. The maximum emission wavelength is λmax=631 nm.

Pb2(SeO3)(SiF6): the first selenite fluorosilicate with a wide bandgap and large birefringence achieved through perfluorinated group modification

“…Bond valence calculations indicate that the oxidation state of Se(1) is 3.958. The oxidation state of Si(1) is 4.513, which is relatively elevated and commonly observed in hexafluoro silicate compounds, such as compounds KLiSiF 6 (Si: 4.496), 48 Tl 2 SiF 6 (Si: 4.506) 49 and Li 2 SiF 6 (Si: 4.518). 50 Given that it is not an isolated case, we believe the high bond valence may be caused by the overestimated bond valence parameter (1.58) for the Si 4+ –F bond.…”

Trendbericht Festkörperchemie 2022

“…Huppertz synthetisierte in Zusammenarbeit mit Kraus KLiSiF 6 und CsLiSiF 6 über eine Hochdruck-Hochtemperatur-Synthese. 33) Beide Verbindungen kristallisieren in der Raumgruppe Pbcn, enthalten aber unterschiedliche Baueinheiten: eine [LiF 6 ] 5--Einheit in KLiSiF 6 und eine [LiF 5 ] 4--Einheit in CsLiSiF 6 . KLiSiF 6 lässt sich mit Mn 4+ dotieren und photoluminesziert daraufhin rot.…”