View source for Chemistry:Tetranitratoborate

'''Tetranitratoborate''' is an anion composed of boron with four nitrate groups. It has formula {{chem2|[B(NO3)4]−}}. It can form salts with large cations such as [[Chemistry:Tetramethylammonium|tetramethylammonium]] nitratoborate,<ref name="Guibert1966">{{cite journal|last=Guibert|first=C. R.|author2=M. D. Marshall |year=1966|title=Synthesis of the Tetranitratoborate Anion|journal=Journal of the American Chemical Society|volume=88|issue=1|pages=189–190|issn=0002-7863|doi=10.1021/ja00953a051}}</ref> or [[Chemistry:Tetraethylammonium|tetraethylammonium]] tetranitratoborate.<ref name="Titova1970"/> The ion was first discovered by C. R. Guibert and M. D. Marshall in 1966 after failed attempts to make neutral (non-ionic) '''boron nitrate''', {{chem2|B(NO3)3}},<ref name="Guibert1966" /> which has resisted attempts to make it; if it exists, it is unstable above −78&nbsp;°C.<ref name="Titova1970" />

Other related ions are the slightly more stable tetraperchloratoborates, with perchlorate groups instead of nitrate, and [[Chemistry:Tetranitratoaluminate|tetranitratoaluminate]]<ref name="Jones2007">{{cite book|last=Jones|first=CJ Bigler|title=Transition and Main Group Metals Applied to Oxidative Functionalization of Methane and Use as High Oxygen Carriers for Rocket Propellants|url=https://books.google.com/books?id=ELjafGhBa3EC&pg=PA139|accessdate=3 February 2014|year=2007|isbn=9780549231066|page=139}}</ref> with the next atom down the periodic table, aluminium instead of boron ({{chem2|[Al(NO3)4]−}}).

==Formation ==
[[Chemistry:Tetramethylammonium chloride|Tetramethylammonium chloride]] reacts with [[Chemistry:Boron trichloride|{{chem2|BCl3}}]] to make {{chem2|[N(CH3)4]+[BCl4]−}}. Then the tetrachloroborate is reacted with [[Chemistry:Dinitrogen tetroxide|{{chem2|N2O4}}]] at around −20&nbsp;°C to form tetramethylammonium nitratoborate, and other gases such as [[Chemistry:Nitryl chloride|{{chem2|NO2Cl}}]] and [[Chemistry:Chlorine|{{chem2|Cl2}}]].<ref name="Titova1970"/>

Another mechanism to make tetranitratoborate salts is to shake a metal nitrate with {{chem2|BCl3}} in chloroform at 20&nbsp;°C for several days. Trichloronitratoborate {{chem2|[BCl3(NO3)]−}} is an unstable intermediate.

:{{chem2|M+NO3− + BCl3 → M+[BCl3(NO3)]−}}

:{{chem2|4 M+[BCl3(NO3)]− → 3 M+[BCl4]− + M+[B(NO3)4]−}}<ref name="Titova1975">{{cite journal|last=Titova|first=K. V.|author2=V. Ya. Rosolovskii |year=1975|title=Reaction of nitrates of monovalent cations with BCl<sub>3</sub>|journal=Bulletin of the Academy of Sciences of the USSR Division of Chemical Science|volume=24|issue=10|pages=2246–2248|issn=0568-5230|doi=10.1007/BF00929774}}</ref>

==Properties==
The infrared spectrum of tetramethylammonium nitratoborate includes a prominent line at 1,612&nbsp;cm<sup>−1</sup> with shoulders at 1582 and 1,626&nbsp;cm<sup>−1</sup> attributed to ''v''<sub>4</sub>. Also prominent is 1,297 and 1,311&nbsp;cm<sup>−1</sup> attributed to ''v''<sub>1</sub>, with these vibrations due to the nitrate bonded via one oxygen.<ref name="Guibert1966"/>

The density of tetramethylammonium nitratoborate is 1.555&nbsp;g·cm<sup>−3</sup>. It is colourless and crystalline. As tetramethylammonium nitratoborate is heated it has some sort of transition between 51 and 62&nbsp;°C. It decomposes above 75&nbsp;°C producing gas. Above 112&nbsp;°C it is exothermic, and a solid is left if it is heated to 160&nbsp;°C.<ref name="Titova1970">{{cite journal|last=Titova|first=K. V.|author2=V. Ya. Rosolovskii |year=1970|title=Tetraalkylammonium nitratoborates|journal=Bulletin of the Academy of Sciences of the USSR Division of Chemical Science|volume=19|issue=12|pages=2515–2519|issn=0568-5230|doi=10.1007/BF00854900}}</ref>

Tetramethylammonium nitratoborate is insoluble in cold water but slightly soluble in hot water. It does not react with water. It also dissolves in liquid ammonia, acetonitrile, methanol, and [[Chemistry:Dimethylformamide|dimethylformamide]].<ref name="Guibert1966"/> It reacts with liquid [[Chemistry:Sulfur dioxide|sulfur dioxide]].<ref name="Guibert1966"/><ref name="Addison">{{cite book|author1=C.C. Addison |author2=D. Sutton |title=Progress in Inorganic Chemistry|volume=8|page=216}}</ref>

At room temperature tetramethylammonium nitratoborate is stable for months. It does not explode with impact.<ref name="Guibert1966"/>

Alkali metal tetranitratoborates are unstable at room temperature and decompose.<ref name="Titova1975"/>

1-Ethyl-3-methyl-imidazolimium tetranitratoborate was discovered in 2002. It is an ionic liquid that turns solid at −25&nbsp;°C.<ref name="Jones2006">{{cite journal|last=Jones|first=C. Bigler|author2=Ralf Haiges |author3=Thorsten Schroer |author4=Karl O. Christe |year=2006|title=Oxygen-Balanced Energetic Ionic Liquid|journal=Angewandte Chemie International Edition|volume=45|issue=30|pages=4981–4984|issn=1433-7851|doi=10.1002/anie.200600735 |pmid=16819744|doi-access=free}}</ref>

==References==
{{reflist|30em}}

{{nitrates}}
{{boron compounds}}

[[Category:Nitrates]]
[[Category:Boron compounds]]
[[Category:Borates]]
[[Category:Anions]]

{{Sourceattribution|Tetranitratoborate}}