Die Kristallstruktur von KTlF 4 / Crystal Structure of KTlF 4

The results of X-ray structure determinations on single crystals of KTlF 4 are reported. The unit cell is trigonal with α = 8.025, c = 10.16 A, Z = 6; space group: P 3 1 - C 2 3 . KTlF 4 is a new superstructure variant of the CaF 2 -type. Each Tl is coordinated by 7, K by 8 resp. 9 F. Other A+B 3 +F 4 -type compounds (A+ = Na, Ag, K; B 3+ = In, Tl, Ln) are isostructural with KTlF 4 .