Magnetic Frustration in a Zeolite

Abstract

Zeolites are so well known in real-world applications and after decades of scientific study that they hardly need any introduction: their importance in chemistry cannot be overemphasized. Here, we add to the remarkable properties that they display by reporting our discovery that the simplest zeolite, sodalite, when doped with Cr3+ in the β-cage, is a frustrated magnet. Soft X-ray absorption spectroscopy and magnetic measurements reveal that the Cr present is Cr(III). Cr(III), with its isotropic 3d3 valence electron configuration, is well known as the basis for many geometrically frustrated magnets, but it is especially surprising that a material like the Ca8Al12Cr2O29 zeolite is a frustrated magnet. This finding illustrates the value of exploring the properties of even well-known material families.