The neutral azatricarbaborane 7-t-Bu-arachno-7,1,5,12-NC3B8H12, isolated as a side product (yield 2%) from the new synthesis of 7-t-BuNH2-nido-7,8,9-C3B8H10 (yield 70%), can be easily converted to the first parent representatives of the 10-vertex nido fa