The main component of the atmosphere in Mars is carbon dioxide. More than 95% of its atmosphere is composed of this while the rest is composed of nitrogen and all the other gases in minimal amounts. There is a lot of iron that can be found on Mars. Aside from that, there are also minerals that form the surface of Mars such as calcium, aluminum, and magnesium.
Based on the details regarding its surface and its atmosphere, it is evident that it can be quite impossible for people to try living on this planet. It will take a lot of effort before it can be considered livable. The options that are being thought of may not even be possible.