K3Sn5Cl3F10with a corrugated layered structure

Single crystals of K3Sn5Cl3F10, tri­potassium trichloro­deca­fluoro­penta­stannate(II), were isolated from a batch of needle-shaped crystals containing several potassium tin(II) fluorides, chlorides and chloride fluorides. The title compound crystallizes in the centrosymmetric space group Cmcm and the unit cell contains three crystallographically distinct tin units, with one SnF3Cl2E, in the unusual SnX5E pseudo-octa­hedral coordination, while the other two are in an SnX4E pseudo-trigonal bipyramid (E is a stereoactive lone pair). The SnF3Cl2 units form [SnF2Cl2]n2n− rows parallel to the a axis of the unit cell, sandwiched between rows of [Sn2F4]n units also parallel to the a axis, with adjacent [Sn2F4]n rows being held together by rows of Cl− ions, also parallel to a. This ensemble forms [(Sn2F4)(SnF2Cl2)(Sn2F4)Cl]n3n− anionic planes parallel to ac. Two adjacent anionic planes, their terminal F atoms pointing towards each other, are held together by K+ ions and form bilayers. Each pair of adjacent bilayers is separated by a sheet of Sn lone pairs, making the structure highly layered.