calcium peroxide

[the guy]

if calcium carbonate is heated in oxygen, will it form calcium peroxide aswell as/ instead of calcium oxide?

[John Cuthber]

No.

[dttom]

You got to check the stability of this compound, calcium peroxide. And you will see it really is an unstable one. Calcium ion is small compared to the large and polarizable peroxide ion, significant distortion in electron cloud resluts in instability. Other explanation should be possible, like if you treat this ionic compound as an acid-base adduct, based on the principle of hard-soft-acid-base theory you probably got the same conclusion.