Editing Boron nitride (section)

==Synthesis==
===Preparation and reactivity of hexagonal BN===
Hexagonal boron nitride is obtained by the treating boron trioxide ({{chem2|B2O3}}) or boric acid ({{chem2|H3BO3}}) with [[ammonia]] ({{chem2|NH3}}) or [[urea]] ({{chem2|CO(NH2)2}}) in an inert atmosphere:<ref name=prod>{{cite journal | author = Rudolph, S. | journal = American Ceramic Society Bulletin | volume = 79 | year = 2000 | page = 50 | url = http://www.a-m.de/deu/literatur/cb0600.html | title = Boron Nitride (BN) | url-status = dead | archive-url = https://web.archive.org/web/20120306221940/http://www.a-m.de/deu/literatur/cb0600.html | archive-date = 2012-03-06}}</ref>

:{{chem2|B2O3 + 2 NH3 → 2 BN + 3 H2O}} (''T'' = 900&nbsp;°C)
:{{chem2|B(OH)3 + NH3 → BN + 3 H2O}} (''T'' = 900&nbsp;°C)
:{{chem2|B2O3 + CO(NH2)2 → 2 BN + CO2 + 2 H2O}} (''T'' > 1000&nbsp;°C)
:{{chem2|B2O3 + 3 CaB6 + 10 N2 → 20 BN + 3 CaO}} (''T'' > 1500&nbsp;°C)

The resulting disordered ([[amorphous solid|amorphous]]) material contains 92–95% BN and 5–8% {{chem2|B2O3}}. The remaining {{chem2|B2O3}} can be evaporated in a second step at temperatures {{nowrap|> 1500 °C}} in order to achieve BN concentration >98%. Such annealing also crystallizes BN, the size of the crystallites increasing with the annealing temperature.<ref name=dkg/><ref>{{cite web | url = http://hubacek.jp/bn/bn.htm | access-date = 2009-06-06 | title = Synthesis of Boron Nitride from Oxide Precursors | archive-url = https://web.archive.org/web/20071212115253/http://hubacek.jp/bn/bn.htm | archive-date = December 12, 2007 | url-status=dead}}</ref>

h-BN parts can be fabricated inexpensively by hot-pressing with subsequent machining. The parts are made from boron nitride powders adding boron oxide for better compressibility. Thin films of boron nitride can be obtained by [[chemical vapor deposition]] from [[borazine]].<ref>A. J. R. Payne, N. F. X. Jr, A. Tamtögl, M. Sacchi, Unravelling the Epitaxial Growth Mechanism of Hexagonal and Nanoporous Boron Nitride: A First-Principles Microkinetic Model. Small 2025, 2405404. https://doi.org/10.1002/smll.202405404</ref> [[ZYP Coatings (company)|ZYP Coatings]] also has developed boron nitride coatings that may be painted on a surface. Combustion of boron powder in nitrogen [[plasma (physics)|plasma]] at 5500&nbsp;°C yields [[Ultrafine particles|ultrafine]] boron nitride used for lubricants and [[toner (printing)|toner]]s.<ref>{{cite journal |author1=Paine, Robert T. |author2=Narula, Chaitanya K. | title = Synthetic Routes to Boron Nitride | journal = Chemical Reviews | year = 1990 | volume = 90 | pages = 73–91 | doi= 10.1021/cr00099a004}}</ref>

Boron nitride reacts with [[iodine monofluoride|iodine fluoride]] to give {{chem2|NI3}} in low yield.<ref>{{cite journal |author1=Tornieporth-Oetting, I. |author2=Klapötke, T. | journal = Angewandte Chemie International Edition | year = 1990 | volume = 29 | pages =677–679 | doi = 10.1002/anie.199006771 | title = Nitrogen Triiodide | issue = 6}}</ref>
Boron nitride reacts with nitrides of lithium, alkaline earth metals and lanthanides to form [[nitridoborate]]s.<ref name = "Housecroft2d">{{cite book |author1=Housecroft, Catherine E. |author2=Sharpe, Alan G. | year=2005 |title=Inorganic Chemistry|edition=2d |publisher=Pearson education|pages=318|isbn=978-0-13-039913-7}}</ref> For example:
:{{chem2|Li3N + BN → Li3BN2}}

===Intercalation of hexagonal BN===
{{see also|Graphite intercalation compound|Graphene boron nitride nanohybrid materials}}
[[Image:BN8Kstructure.jpg|150px|thumb|Structure of hexagonal boron nitride intercalated with potassium ({{chem2|B4N4K}})]]

Various species intercalate into hexagonal BN, such as {{chem2|NH3}} intercalate<ref>{{cite journal | author = Solozhenko, V. L. | journal = Physical Chemistry Chemical Physics | year = 2002 | page = 5386 | doi = 10.1039/b206005a | title = ''In situ'' Studies of Boron Nitride Crystallization from BN Solutions in Supercritical N–H Fluid at High Pressures and Temperatures | volume = 4 | issue = 21 |bibcode = 2002PCCP....4.5386S |display-authors=etal}}</ref> or alkali metals.<ref>{{cite journal | author = Doll, G. L. | title = Intercalation of Hexagonal Boron Nitride with Potassium | journal = Journal of Applied Physics | volume = 66 | page = 2554 | year = 1989 | doi = 10.1063/1.344219 | issue = 6 |bibcode = 1989JAP....66.2554D |display-authors=etal}}</ref>

===Preparation of cubic BN===
c-BN is prepared analogously to the preparation of [[synthetic diamond]] from graphite. Direct conversion of hexagonal boron nitride to the cubic form has been observed at pressures between 5 and 18&nbsp;GPa and temperatures between 1730 and 3230&nbsp;°C, that is similar parameters as for direct graphite-diamond conversion.<ref name=wentorf>{{cite journal | author = Wentorf, R. H. Jr. | author-link = Robert H. Wentorf, Jr. |date=March 1961 | title = Synthesis of the Cubic Form of Boron Nitride | journal = Journal of Chemical Physics | volume = 34 | issue = 3 | pages = 809–812 | doi = 10.1063/1.1731679 |bibcode = 1961JChPh..34..809W}}</ref> The addition of a small amount of boron oxide can lower the required pressure to 4–7&nbsp;GPa and temperature to 1500&nbsp;°C. As in diamond synthesis, to further reduce the conversion pressures and temperatures, a catalyst is added, such as lithium, potassium, or magnesium, their nitrides, their fluoronitrides, water with ammonium compounds, or hydrazine.<ref name=vel>{{cite journal | doi = 10.1016/0921-5107(91)90121-B | title = Cubic Boron Nitride: Synthesis, Physicochemical Properties and Applications | author = Vel, L. | journal = Materials Science and Engineering: B | volume = 10 | year = 1991 | page = 149 | issue = 2 |display-authors=etal}}</ref><ref>{{cite journal | author = Fukunaga, O. | title = Science and Technology in the Recent Development of Boron Nitride Materials | year = 2002 | journal = Journal of Physics: Condensed Matter | volume = 14 | page = 10979 | doi = 10.1088/0953-8984/14/44/413 | issue = 44 |bibcode = 2002JPCM...1410979F | s2cid = 250835481}}</ref> Other industrial synthesis methods, again borrowed from diamond growth, use crystal growth in a temperature gradient, or explosive [[shock wave]]. The shock wave method is used to produce material called [[heterodiamond]], a superhard compound of boron, carbon, and nitrogen.<ref>{{cite journal | author = Komatsu, T. | title = Creation of Superhard B–C–N Heterodiamond Using an Advanced Shock Wave Compression Technology | journal = Journal of Materials Processing Technology | volume = 85 | issue = 1–3 | year = 1999 | page = 69 | doi = 10.1016/S0924-0136(98)00263-5 |display-authors=etal}}</ref>

Low-pressure deposition of thin films of cubic boron nitride is possible. As in diamond growth, the major problem is to suppress the growth of hexagonal phases (h-BN or graphite, respectively). Whereas in diamond growth this is achieved by adding hydrogen gas, [[boron trifluoride]] is used for c-BN. [[Ion beam deposition]], [[plasma-enhanced chemical vapor deposition]], [[pulsed laser deposition]], [[Sputter deposition|reactive sputtering]], and other [[physical vapor deposition]] methods are used as well.<ref name=cvd>{{cite journal | title = Review of Advances in Cubic Boron Nitride Film Synthesis | author = Mirkarimi, P. B. | volume = 21 | year = 1997 | pages = 47–100 | doi = 10.1016/S0927-796X(97)00009-0 | journal = Materials Science and Engineering: R: Reports | issue = 2 |display-authors=etal| url = https://zenodo.org/record/1260151}}</ref>

===Preparation of wurtzite BN===
Wurtzite BN can be obtained via static high-pressure or dynamic shock methods.<ref>{{cite journal | title = Characterization of Wurtzite Type Boron Nitride Synthesized by Shock Compression | author = Soma, T. | journal = Materials Research Bulletin | volume = 9 | year = 1974 | page = 755 | doi = 10.1016/0025-5408(74)90110-X | issue = 6 |display-authors=etal}}</ref> The limits of its stability are not well defined. Both c-BN and w-BN are formed by compressing h-BN, but formation of w-BN occurs at much lower temperatures close to 1700&nbsp;°C.<ref name=vel/>

===Production statistics===
Whereas the production and consumption figures for the raw materials used for BN synthesis, namely boric acid and boron trioxide, are well known (see [[boron]]), the corresponding numbers for the boron nitride are not listed in statistical reports. An estimate for the 1999 world production is 300 to 350 [[metric tons]]. The major producers and consumers of BN are located in the United States, Japan, China and Germany. In 2000, prices varied from about $75–120/kg for standard industrial-quality h-BN and were about up to $200–400/kg for high purity BN grades.<ref name=prod/>