C10200 oxygen-free copper is pure copper that does not contain oxygen or any deoxidizer residues. But in fact it still contains a very small amount of oxygen and some impurities. 

According to the standard, the oxygen content is not more than 0.003%, the total impurity content is not more than 0.05%, and the copper purity is more than 99.95%

Chemical composition 
CU+AG (%）：：≥99.95
Sn ：≤0.002
Zn：≤0.003
Pb：≤0.003
 Pb：≤0.003
P：≤0.002
Ni：≤0.002
Fe：≤0.004
Sb ：≤0.002
 S ：≤0.004
As ：≤0.002
 Bi：≤0.001
 O：≤0.003
others：≤0.05(impurities)