If you get it cold enough, yes.

Under normal pressure, oxygen freezes at -218.4 C and boils at -183 C.

If you’re insane enough or suicidal enough to isolate pure oxygen and then freeze it. Because you are a danger warrior, and liquid oxygen, the closest thing to purified, concentrated essence of malevolence you’re ever likely to see, is not dangerous enough for you, oh no.

You get ‘em, Tiger. You’re the sort who snorts fluorine to clear your sinuses and uses liquid oxygen to clean grease stains out of your clothes (at which task it excels, by the way), and you want to live the high life. You want to take it up a notch.

So you chill some liquid oxygen to around 54k and yup…it will in fact freeze.

And now you have a solid chunk of extremely concentrated, highly dense, ravenously electronegative hate that is doing absolutely everything in its power to kill you all the time.

You’d be amazed what will become flammable around solid oxygen that you don’t normally think of as flammable, and what a gentle nudge it takes to get it over that activation energy hump.