High‐Pressure Synthesis of Metal–Inorganic Frameworks Hf<sub>4</sub>N<sub>20</sub>⋅N<sub>2</sub>, WN<sub>8</sub>⋅N<sub>2</sub>, and Os<sub>5</sub>N<sub>28</sub>⋅3 N<sub>2</sub> with Polymeric Nitrogen Linkers
Angewandte Chemie