Preparation and Crystal Structure of the New Quaternary Europium‐polysulfide KCuEu 2 s 6

The new quaternary europium polysulfide KCuEu 2 S 6 was obtained using the reactive flux method at an intermediate temperature of 380°C by reacting K 2 S 3 with elemental Cu, EuS and an excess of sulfur. The Eu 3+ ions exhibit a bicapped trigonal prismatic coordination and the Cu + ions are in a tetrahedral environment. The crystal structure is characterized by anionic layers of interconnected Eu and Cu polyhedra with K + ions residing between the anionic sheets [Cu‐Eu 2 S 6 ] n n — . The Cu + ions occupy one half of the tetrahedral sites in an ordered fashion.