PbFePO4F2 with a 1/6th bond depleted triangular lattice

Abstract

We hydrothermally synthesized a layered PbFePO₄F₂ (P2₁/n). Fe³⁺ cations (S = 5/2) within the layer are connected via F⁻ and (PO₄)^3– anions to give a novel (distorted) 1/6th bond depleted triangular lattice. The χ(T) suggests strong antiferromagnetic interactions with a Weiss constant of −125 K, but geometrical frustration and low dimensionality appear to prohibit a long-range order down to 23 K.