Question

why carbon does not form ionic compound?

Answer 1

To form ionic bonds, Carbon molecules must either gain or lose 4 electrons. This is highly unfavorable; therefore, carbon molecules share their 4 valence electrons through single, double, and triple bonds so that each atom can achieve noble gas configurations.

Answer 2

Becocoz it is versatile element,
It has property of catenation
And it shares the valence electron