Like many metals, it does not form itself into molecules (not the way we understand "molecule" in chemistry). However, the atoms will form crystals and these can go on forever (as long as you have pure chromium available).
Thus, if you are dealing with pure chromium and you want to determine properties (for example, the mass of one mole), you treat it like a "molecule" of one atom. Unlike a real molecule, the single atom will not have satisfied its outer electron layers (it still have valences, a willingness to combine with other atoms); it's just that it does not care about combining with itself.
It will readily combine with oxygen (like iron when it rusts) but in the case of Chromium, a coating of Chromium oxide (one or two molecules thick) is sufficient to stop the oxygen from attacking the rest of the Chromium. It provides its own anti-rust coating.