Accessing Tetravalent Transition-Metal Nitridophosphates through High-Pressure Metathesis

Advancing the attainable composition space of a compound class can lead to fascinating materials. The first tetravalent metal nitridophosphate, namely Hf9-xP24N52-4xO4x (x approximate to 1.84), was prepared by high-pressure metathesis. The Group4 nitridophosphates are now an accessible class of compounds. The high-pressure metathesis reaction using a multianvil setup yielded single crystals that were suitable for structure analysis. Magnetic properties of the compound indicate Hf in oxidation state +IV. Optical measurements show a band gap in the UV region. The presented route unlocks the new class of Group4 nitridophosphates by significantly improving the understanding of this nitride chemistry. Hf9-xP24N52-4xO4x (x approximate to 1.84) is a model system and its preparation is the first step towards a systematic exploration of the transition-metal nitridophosphates.