In the transformation of oxyhemoglobin to deoxyhemoglobin:
1
\(Fe^{2+}\) in low spin state changes to \(Fe^{2+}\) in high spin state
2
\(Fe^{2+}\) in low spin state changes to \(Fe^{3+}\) in low spin state
3
\(Fe^{2+}\) in high spin state changes to \(Fe^{2+}\) in low spin state
4
\(Fe^{2+}\) in high spin state changes to \(Fe^{2+}\) in high spin state