Uncovering the [Image: see text] Kagome Ferromagnet within a Family of Metal–Organic Frameworks

[Image: see text] Kagome networks of ferromagnetically or antiferromagnetically coupled [Image: see text] magnetic moments represent important models in the pursuit of a diverse array of novel quantum and topological states of matter. Here, we explore a family of Cu(2+)-containing metal–organic frameworks (MOFs) bearing [Image: see text] kagome layers pillared by ditopic organic linkers with the general formula Cu(3)(CO(3))(2)(x)(3)·2ClO(4) (MOF-x), where x is 1,2-bis(4-pyridyl)ethane (bpe), 1,2-bis(4-pyridyl)ethylene (bpy), or 4,4′-azopyridine (azpy). Despite more than a decade of investigation, the nature of the magnetic exchange interactions in these materials remained unclear, meaning that whether the underlying magnetic model is that of an [Image: see text] kagome ferromagnet or antiferromagnet is unknown. Using single-crystal X-ray diffraction, we have developed a chemically intuitive crystal structure for this family of materials. Then, through a combination of magnetic susceptibility, powder neutron diffraction, and muon-spin spectroscopy measurements, we show that the magnetic ground state of this family consists of [Image: see text] ferromagnetic kagome layers that are coupled antiferromagnetically via their extended organic pillaring linkers.