Potassium sodium tin selenide, K3NaSn3Se8.

The title compound, tripotassium sodium tritin octaselenide, K(3)NaSn(3)Se(8), has a molecular (zero-dimensional) structure containing trimeric [Sn(3)Se(8)](4-) units which consist of three edge-sharing SnSe(4) tetrahedra. The [Sn(3)Se(8)](4-) anions and the tetrahedrally coordinated Na(+) cations are arranged in an alternating fashion along the c axis to form SiS(2)-like chains, which are then separated by eight-coordinate K(+) cations. The Sn-Se bond distances are normal, being in the range 2.477 (1)-2.612 (1) A.