K15NaSn5F36 crystallizes in the hexagonal crystal system with space group P63/m and lattice parameters of a = 1060.3(2) and c = 2011.9(4) pm. The unit-cell volume amounts to 1.9588(7) nm3. Its fundamental building blocks are quasi-isolated [SnF6]2− and [NaF6]5− octahedra, which are imbedded into a matrix of potassium cations. Within the structure, these units form a layer-like arrangement consisting either of mixed [SnF6]2−/[NaF6]5− or pure [SnF6]2− layers. The structural model was further confirmed by BLBS and CHARDI calculations.