From Framework to Layers Driven by Pressure – The Monophyllo‐Oxonitridophosphate β‐MgSrP₃N₅O₂ and Comparison to its α‐Polymorph

Abstract

Abstract Oxonitridophosphates exhibit the potential for broad structural diversity, making them promising host‐compounds in phosphor‐converted light‐emitting diode applications. The novel monophyllo‐oxonitridophosphate β‐MgSrP 3 N 5 O 2 was obtained by using the high‐pressure multianvil technique. The crystal structure was solved and refined based on single‐crystal X‐ray diffraction data and confirmed by powder X‐ray diffraction. β‐MgSrP 3 N 5 O 2 crystallizes in the orthorhombic space group Cmme (no. 67, a =8.8109(6), b =12.8096(6), c =4.9065(3) Å, Z= 4) and has a structure related to that of Ba 2 CuSi 2 O 7 . DFT calculations were performed to investigate the phase transition from α‐ to β‐MgSrP 3 N 5 O 2 and to confirm the latter as the corresponding high‐pressure polymorph. Furthermore, the luminescence properties of Eu 2+ doped samples of both polymorphs were investigated and discussed, showing blue and cyan emission, respectively (α‐MgSrP 3 N 5 O 2 ; λ max =438 nm, fwhm =46 nm/2396 cm −1 ; β‐MgSrP 3 N 5 O 2 ; λ max =502 nm, fwhm =42 nm/1670 cm −1 ).