Antiperovskite Nitridophosphate Oxide Ho 3 [PN 4 ]O by High‐Pressure Metathesis

Rare‐earth nitridophosphates are a recently discovered class of materials, which are accessible by high‐pressure metathesis. Antiperovskite‐type Ho 3 [PN 4 ]O was synthesized from HoF 3 , LiPN 2 , Li 3 N, and Li 2 O at 5 GPa and ca. 1025 °C by this method and the multianvil technique. Ho 3 [PN 4 ]O contains rarely observed isolated PN 4 tetrahedra and can be derived by the hierarchical substitution of the ABX 3 perovskite, in which Ho occupies the X positions, O occupies the B position, and the PN 4 tetrahedra occupy the A position. The structure was refined on the basis of powder diffraction data [ I 4/ mcm, a = 6.36112(3), c = 10.5571(1) Å, Z = 4, R wp = 0.04, R Bragg = 0.01, χ 2 = 2.275] starting from the structural model of isotypic Gd 3 [SiN 3 O]O. To characterize Ho 3 [PN 4 ]O, elemental analyses were performed through energy‐dispersive X‐ray spectroscopy (EDX) and inductively coupled plasma optical emission spectroscopy (ICP‐OES). Ho 3 [PN 4 ]O is paramagnetic down to low temperatures with µ eff = 10.43(1) µ B and a Curie temperature ( Θ ) of 0.11(4) K. It shows the optical characteristics of Ho 3+ ions and vibrations corresponding to isolated PN 4 tetrahedra. On the basis of DFT calculations [generalized gradient approximation (GGA)], Ho 3 [PN 4 ]O has an indirect band gap of 1.87 eV. We demonstrate the versatility of high‐pressure metathesis by attaining the low end of the P/N atomic ratio κ = 1/4. This confirms the previous assumption that rare‐earth nitridophosphates with κ = 1/2 to 1/4 are feasible by this method.