# Does C8H2N4 (in pentagon shape) exist and what is it called?

My primary school released a folder which contains some sketches. As you can see, they included two molecules. One of them is isopropanol. What's the name of the other molecule (bottom)? Does it exist? The formula would be $$\ce{C8H2N4}$$. It needs to be in a pentagon shape. I guess it has something "tri cyano cyclo penta" in the name.

• The formula reported in the first and in the second picture are not finished. The nitrogen atom down at left should be attached to two H atoms. These two H atoms are correctly reported in the third picture, with spherical atoms. The total number of H atoms is $4$, and not $2$. Sep 9 '21 at 20:07
• I suspect the scribble you are interpreting as as N at the bottom is not related to the structure and that carbon is supposed to be a CH2 group so the core structure is cyclopentadiene and the overall molecule is tricycanocyclopentadiene. Sep 9 '21 at 21:02
• Then again, at this level of precision N might well be a part of the structure, and even a part of the ring (as in pyrrole). Who cares. All suggested molecules exist, but are not particularly famous or important. Sep 9 '21 at 21:33

Aside apparent possibilities of a made-up structure or structure being a fragment ripped off from a larger heterocycle by the designer, there is a third one. Let's pretend the black dash next to the label ‘N’ on the bottom is a minus sign. Then we have 2,3,4‐tricyano‐1H‐pyrrol‐1‐ide $$\ce{C7HN4-}$$:
I haven't found this exact structure, but a more symmetrical tetracyanopyrrolide anion $$\ce{C8N5-}$$ (2,3,4,5-tetracyanopyrrol-1-ide, TCP) is well-known and has been structurally characterized with single crystal diffraction [1] (see also supplementary structures with CSD IDs PEMTOS, PEMTUY and PEMVAG).
Figure 1. Fragment of the crystal structure of tetramethylammonium 2,3,4,5-tetracyanopyrrol-1-ide (CSD ID: PEMTOS). Color code: $$\color{#EEEEEE}{\Large\bullet}~\ce{H};$$ $$\color{#909090}{\Large\bullet}~\ce{C};$$ $$\color{#3050F8}{\Large\bullet}~\ce{N}.$$