Wikipedia
Tetranitratoborate
Tetranitratoborate is an anion composed of boron with four nitrate groups. It has formula [B(NO)]. It can form salts with large cations such as tetramethyl ammonium nitratoborate, or tetraethyl ammonium tetranitratoborate.
The ion was first discovered by C. R. Guibert, M. D. Marshall in 1966 after failed attempts to make boron nitrate.
The related molecule, boron nitrate B(NO), has resisted attempts to make it, and if it exists it is unstable above -78 °C.
Other related ions are the slightly more stable tetraperchloratoborates, with perchlorate groups instead of nitrate, and tetranitratoaluminate with the next atom down the periodic table, aluminium instead of boron ([Al(NO)]).