Novel ternary compound Ce4Pt9Al13: Crystal structure, physical properties

Highlights: • The novel ternary compound Ce₄Pt₉Al₁₃ crystallizes with its own structure type. • The Ce₄Pt₉Al₁₃ structure type is a "site exchange" variant of the Ho₄Ir₁₃Ge₉-type. • Ce₄Pt₉Al₁₃ is characterized by the hexagonal-prismatic environment of the Ce atoms. • Ce₄Pt₉Al₁₃ exhibits a Curie-Weiss paramagnetic behavior due to Ce³⁺ valence state. • Physical properties are influenced by crystalline electric field and Kondo effects. The crystal structure of the novel Al-rich intermetallic phase Ce₄Pt₉Al₁₃ was determined from single-crystal X-ray diffraction data and confirmed by powder X-ray diffraction. The compound crystallizes with its own structure type, which is a "site exchange" variant of the Ho₄Ir₁₃Ge₉-type (Pearson symbol oP52, space group Pmmn, No. 59, Z = 2, lattice parameters: a = 4.1826(1) Å, b = 11.4424(3) Å, c = 19.8475(5) Å, V = 949.88(7) ų). The magnetic properties of Ce₄Pt₉Al₁₃ were determined in the temperature range 1.72–400 K. Down to the lowest temperatures studied, the compound shows a Curie-Weiss paramagnetic behavior with strong crystalline electric field contribution observed below about 200 K. The electrical conductivity in Ce₄Pt₉Al₁₃ has metallic character, and at low temperatures it is governed by an interplay of strong crystal field and Kondo interactions.