C8H7N - the compound formerly known as indol (according to Webster 1913). This aromatic compound is found in some plants, and coal tar, and used in jasmine and orange blossom perfume. If you're into chemistry, you might be interested to know that its molecules consist of a benzene ring fused to a nitrogen-containing five-membered ring. It melts at 52 degrees C and boils at 253 degrees C.

However, indole is more commonly known thanks to the bacteria which can produce it as a by-product of breaking down the amino acid tryptophan in your intestines. In other words, indole is the reason your shit stinks.*

Cf. mercaptan, skatole and hydrogen sulfide.