oxalate(out) + formate(in) => oxalate(in) + formate(out)
oxalate(out) + formate(in) => oxalate(in) + formate(out)
oxalate(out) + formate(in) => oxalate(in) + formate(out)
oxalate(out) + formate(in) => oxalate(in) + formate(out)