Comparisons between Haydeeite, α-Cu₃Mg(OD)₆Cl₂, and Kapellasite, α-Cu₃Zn(OD)₆Cl₂, Isostructural S = 1/2 Kagome Magnets

The search for new S = 1/2 kagome antiferromagnets has been an ongoing challenge for the researchers interested in frustrated magnetism. Intrigue has surrounded these materials since the proposal that the high frustration of the kagome antiferromagnet and quantum fluctuations could prevent the formation of conventional Néel order and allow the formation of the resonating valence bond (RVB) state at low temperatures. There remain relatively few examples of S = 1/2 kagome magnets with crystal structures that have 3-fold symmetry, as many feature distortions that lower the crystal symmetry to monoclinic and reduce the degeneracy of the kagome lattice. In this article, we detail the synthesis and preliminary magnetic investigations of a new quantum kagome magnet, haydeeite, α-Cu 3 Mg(OH) 6 Cl 2 . Comparisons with the isomagnetic and isostructural analogue kapellasite, α-Cu 3 Zn(OH) 6 Cl 2, are discussed.