Trivalent‐Intermediate Valent Cerium Ordering in Ce₂RuZn₄

Abstract

Abstract The new intermetallic cerium compound Ce 2 RuZn 4 was synthesized from the elements in a sealed tantalum tube in a water‐cooled sample chamber of an induction furnace. Ce 2 RuZn 4 crystallizes with a new structure type: P 4/ nmm , Z = 2, a = 719.6(1), c = 520.2(1) pm, wR2 = 0.0816, 273 F 2 values and 15 variables. The structure contains two crystallographically independent cerium atoms: Ce1 with CN 16 (12 Zn + 4 Ce) and Ce2 with CN 14 (2 Ru + 8 Zn + 4 Ce). Based on the interatomic distances the two sites can be assigned to trivalent Ce1 and intermediate valent Ce2. The trivalent‐intermediate valent cerium ordering is underlined by magnetic susceptibility measurements. Ce 2 RuZn 4 shows modified Curie‐Weiss behaviour in the temperature range 10–290 K with an experimental magnetic moment of 2.57(1) μ B per formula unit. Thus only half of the cerium atoms are trivalent in Ce 2 RuZn 4 . A remarkable feature of the Ce 2 RuZn 4 structure are short Ce2–Ru distances of 260 pm. The crystal chemistry of Ce 2 RuZn 4 is discussed.