Nitrogen carbon allotropes

Cataldo, F. Polyynes a new class of carbon allotropes. About the formation of dicyanopolyynes from an electric arc between graphite electrodes in liquid nitrogen. Polyhedron 2004, 23, 1889-1896. 

The a tetragonal form, firstly reported as a boron allotrope, has been reformulated as B50C2 or B50N2, depending on the preparative conditions it never forms in absence of carbon or nitrogen. 

For reasons of completeness it should be pointed out that polymeric sulfur is also obtained if sulfur vapor is quenched from very high temperatures (e.g., 600 °C) to very low temperatures (liquid nitrogen) followed by warming the condensate to -1-20 °C and extraction with carbon disulfide. Up to 60% S have been obtained in this way [53]. Commercially polymeric sulfur (trade name Crystex) is produced by a similar process (see the chapter on Solid Sulfur Allotropes in this volume). The glass transition temperature of Crystex is -1-75 °C [51]. 

We could show that it is possible to get n-type doping effects in carbon based materials using nitrogen as a dopant. The structures where this works, however, are purely sp bonded low energy forms of carbon. The semiconducting allotropes are characterized by unique screw axes of single bonded sp carbon atoms held... 

Carbon, nitrogen, oxygen, phosphorus, and sulfur—a cluster of nonmetals in the periodic table (Figure 5.5)—are extremely important elements. Carbon is important because it is the element upon which all life is based. All organic compounds, which encompasses nearly all 13 million compounds that exist (see Chapter 14), contain carbon. Elemental carbon exists as several different allotropes, or different forms of the same element. These include diamond, graphite, and buckminsterfullerene, which is a form more recently synthesized. Inorganic compounds of carbon are also important. These include... 

---