Borazine (borazol) B3N3H6

Borazine (borazol) B3N3H6 is also called inorganic benzene, because of delocalisation of electrons (unpaired pair of electron from nitrogen atom can fill empty orbital of boron atom), resulting in benzene-type tautomeric forms with double B=N bonds, which cannot be distinguished, the electronic density is evenly distributed across the ring.

Properties: Borazine (borazol) B3H6N3: is colourless liquid (M =80.50 g/mol, d=0.81 g/cm3, m.p. -58°C, b.p. 161°C (55°C at 105 Pa). Accordingly, vapor pressure of borazine is 105 Pa at 55°C.

Borazine B3N3H6 for growth of BN films

    Borazine B3N3H6 was applied as single source precursor for the growth of boron nitride BNx thin films by thermal and plasma enhanced CVD; the composition and structure of the obtained BNx films was studied. Thermal CVD (using either hot-wall or cold-wall reactor) at temperatures 475-550 °C produced amorphous B-rich films with composition BN0.67. However, plasma enhanced CVD consistently resulted in BN films having 1:1 B:N stoichiometry; however the hydrogen content of films grown at temperatures <300 °C was so high layers reacted with atmospheric moisture. Optimum conditions for obtaining stoichiometric BN layers with low H content were: low plasma power, H2/borazine gas mixtures, substrate temperature 550 °C: BN layers deposited under these conditions were mixtures of poorly crystalline hexagonal and cubic BN films.[i]

[i] J. Kouvetakis, V. V. Patel, C. W. Miller, D. B. Beach, J. Vac. Sci. Technol. A 8, 3929 (1990); « Composition and structure of boron nitride films deposited by chemical vapor deposition from borazine », http://dx.doi.org/10.1116/1.576423,   http://scitation.aip.org/content/avs/journal/jvsta/8/6/10.1116/1.576423

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