τεστ

    \[\frac {a+b} {c-d}\]

    \[\chemfig{CΗ_2=CH_2}\]

    \[\chemfig{A-B (=[2]C) -D}\]

    \[\chemfig{A<|B}\]

    \[\chemfig{A-B (-[2]C) (-[:-60]D) -E}\]

    \[\chemfig{A-B (=[2]C) -D}\]

    \[\chemfig{C}\]

\chemfig{H_2}