Ammonium has been isolated in amalgam, but not as the pure pseudometal - it decomposes to ammonia and hydrogen.
... area of 20.0 km² (7.7 mi²). 11.4 km² (4.4 mi²) of it is land and 8.6 km² (3.3 mi²) of it is water. The total area is 42.82% water. ...