a plane landed on the hudson river on january 15, 2009.
when did a plane land on the hudson river?
january 15 , 2009
Na
Na
a fair number of higher polycycles containing the biphenylene nucleus have also been prepared, some having considerable antiaromatic character. in general, additional 6-membered rings add further aromatic character, and additional 4-membered and 8-membered rings add antiaromatic character. however, the exact natures of the additions and fusions greatly affect the perturbations of the biphenylene system, with many fusions resulting in counter-intuitive stabilization by [4n] rings, or destabilization by 6-membered rings. this has led to significant interest in the systems by theoretical chemists and graph theoreticians. even a complete 2-dimensional carbon sheet with biphenylene-like subunits has been proposed
biphenylene