Law and Disorder: Special Stacking UnitsBuilding the Intergrowth Ce₆Co₅Ge₁₆

A new structure type of composition Ce₆Co₅Ge₁₆ was grown out of a molten Sn flux. Ce₆Co₅Ge₁₆ crystallizes in the orthorhombic space group Cmcm, with highly anisotropic lattice parameters of a = 4.3293(5) Å, b = 55.438(8) Å, and c = 4.3104(4) Å. The resulting single crystals were characterized by X-ray diffraction, and the magnetic and transport properties are presented. The Sn-stabilized structure of Ce₆Co₅Ge₁₆ is based on the stacking of disordered Ce cuboctahedra and is an intergrowth of existing structure types including AlB₂, BaNiSn₃, and AuCu₃. The stacking of structural subunits has previously been shown to be significant in the fields of superconductivity, quantum materials, and optical materials. Herein, we present the synthesis, characterization, and complex magnetic behavior of Ce₆Co₅Ge₁₆ at low temperature, including three distinct magnetic transitions.