Nitrogen bonding with boron

Therefore it cannot donate electrons to form a bond. But nitrogen (N) in the ammonia molecule has 1 unshared electron pair and it can therefore form a coordinate covalent bond with boron. 

In contrast, use of metalloid elements, such as silicon, tin antimony or boron, which can form weak covalent bonds with oxygen, nitrogen or sulfur substituents during the course of the reaction, results in templated products that may be obtained metal-free by simple hydrolysis. These covalent template reactions (the M—X bond is essentially covalent in these cases) also have the advantage that the... 

The compound is stable only with nitrogen as a substituent on the boron atom, which supplies electrons for stabilization of the B-Si bonds. Attempts to form a Si-B bond without a Nme2 group were unsuccesful. 

Similar arguments apply to impurity states. Any impurity which is bonded with its optimum valency is expected to form a part of the ideal network and contribute only to the conduction and valence bands. Oxygen, nitrogen, carbon, and germanium all behave in this way, forming alloys with a-Si H. Most of the phosphorus and boron atoms which are added as dopants, are in three-fold coordinated inactive sites... 

Fjeldberg, T., G. Gundersen, T. Jonvik, H. M. Seip, and S. Saebo (1980). Ah initio studies of some trivalent boron compounds with boron-oxygen and boron-nitrogen bonds. Acta. Chem. Stand. A34, 547-65. 

At the root of the instability of fluoroaUcylboron compounds is the availability of a vacant orbital on boron it will be seen that when boron is co-ordinately saturated, as in four-covalent boron derivatives (10.26A), or partially saturated by tt bonding with attached oxygen- or nitrogen-containing groups (10.26B), then the stability of perfluoro-alkylboron compounds increases (Figure 10.26). 

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