Strontium vanadium oxide-hydrides: "square-planar" two-electron phases.

A series of strontium vanadium oxide-hydride phases prepared by utilizing a low-temperature synthesis strategy in which oxide ions in Srn+1VnO3n+1 (n = infinity, 1, 2) phases are topochemically replaced by hydride ions to form SrVO2H, Sr2VO3H, and Sr3V2O5H2, respectively. These new phases contain sheets or chains of apex-linked V3+O4 squares stacked with SrH layers/chains, such that the n = infinity member, SrVO2H, can be considered to be analogous to "infinite-layer" phases, such as Sr1-xCaxCuO2 (the parent phase of the high-T-c cuprate superconductors), but with a d(2) electron count. All three oxide-hydride phases exhibit strong antiferromagnetic coupling, with SrVO2H exhibiting an antiferromagnetic ordering temperature, T-N>300 K. The strong antiferromagnetic couplings are surprising given they appear to arise from p-type magnetic exchange.