Structural and Magnetic Correlations in the Layered Honeycomb Antiferromagnet CrCl₃

CrCl₃ is a layered van der Waals antiferromagnet that serves as a model system for magnetism on the honeycomb lattice. Like the widely investigated Kitaev quantum spin liquid candidate α-RuCl₃, it undergoes a structural transition from monoclinic C2/m to rhombohedral R-3. However, the weak bond-dependent exchange in CrCl₃ makes it an ideal reference for conventional Heisenberg honeycomb magnetism. Using single-crystal neutron diffraction and magnetic diffuse scattering, the evolution of structural stacking across the structure transition and lower-temperature magnetic correlations are investigated. Upon cooling, CrCl₃ develops antiferromagnetic order composed of ferromagnetic layers coupled antiferromagnetically, while diffuse scattering above T_N reveals persistent quasi-two-dimensional spin correlations stabilized by finite interlayer exchange interaction. These results establish CrCl₃ as a benchmark for disentangling structural and magnetic effects in honeycomb magnets, offering a contrast to the spin–orbit–driven physics of α-RuCl₃ and related van der Waals materials.