β Scribed by Frank Kubel
No coin nor oath required. For personal study only.
Two members belonging to the pseudobinary phase diagram of Ba/SrF 2 and AlF 3 were synthesized. Single domain crystals of SrAlF 5 and Ba 0.43(1) Sr 0.57(1) AlF 5 were prepared from the corresponding metal fluorides. The mixed compound Ba 0.43(1) Sr 0.57(1) AlF 5 has been synthesized and characterized in detail for the first time. The structure of SrAlF 5 was reinvestigated; a superstructure was found which is absent in Ba 0.43(1) Sr 0.57(1) AlF 5 . The compounds crystallize at room temperature in the centrosymmetric tetragonal space groups I4 1 /a and I4/m. Lattice parameters are a = b= 1988.22( ), c = 1432.24( ) and a = b = 1431.32( ), c = 722.83(7) pm.
Both structures differ mainly in the AlF 6 arrangement situated in the cavities of the matrix structure. In SrAlF 5 , ordered dimer [Al 2 F 10 ] 4Β± units are found, whereas in the Ba 2+ mixed sample a linear chain of AlF 6 octahedra is observed. For both compounds no partial occupation was observed. Sm 2+ doped samples are further characterized by luminescence measurements. Four independent sites of alkaline earth atoms were found in the Sm 2+ luminescence of the host SrAlF 5 .
π SIMILAR VOLUMES
The title compounds are prepared by reaction of the elements at 850 β’ C with fluxes such as BaCl 2 or an eutectic mixture of LiCl/KCl. Single crystal XRD of all three compounds show tetrahedral structures based on CuTe 4 units. BaDyCuTe 3 crystallizes in the orthorhombic space group Cmcm with Z = 4,