Strontium oxide or strontia, SrO, is formed when strontium reacts with oxygen.

It also forms from the decomposition of strontium carbonate SrCO3.

[3][4] Color televisions and other devices containing color cathode-ray tubes sold in the United States are required by law to use strontium in the faceplate to block X-ray emission (these X-ray emitting TVs are no longer in production).

Lead(II) oxide can be used in the neck and funnel, but causes discoloration when used in the faceplate.

[5] Elemental strontium is formed when strontium oxide is heated with aluminium in a vacuum.