Alpha-boron nitride

Boron nitride [10043-11-5], chemical formula BN, exists as three different poly-morphs alpha-boron nitride (a-BN), a soft and ductile polymorph (p = 2280 kg.m" and m.p. = 2700°C)... 

Since the alpha-ray impacts shattered only a minute proportion of the total number of atoms of boron, aluminum, or magnesium, the chemical identification of the products was extremely difficult. These indefatigable workers, however, accomplished even this. Although it would have been impossible to identify the products simply by ordinary chemical means, the Joliots were able to take advantage of the radioactive nature of the products formed. Since they had good reason to believe that the boron atom had captured a helion and ejected a neutron and that the new element was therefore probably an isotope of nitrogen, they heated some bombarded boron nitride with caustic soda and found that the liberated... 

Samples were exposed to synchrotron radiation through a gold-on-boron nitride mask and then developed using various mixtures of isopropyl alcohol (IPA) and methyl isobutyl ketone (NIBK). Development was conducted under stirred conditions using a constant temperature bath at 23°C and was terminated by blow drying with Freon gas. Film thicknesses were measured using a Tencor Alpha Step. 

The atomic and molecular weights of these boron nitrides are listed in Table 2. Note that B has a large cross section for thermal neutron capture and changes to Li with the emission of an alpha-particle [ B(n, a) Li],... 

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