Construct-in-place an unmoveable object in a map

I'm trying to construct an object in a map that contains an atomic, so it can neither be copied nor moved AFAICT.

My reading of C++ reference is that map emplace should be able to do this. But the following code does not compile because of deleted or non-existent constructors. Using make_pair does not help.

#include <atomic>
#include <unordered_map>

class Z {
  std::atomic<int> i;
};

std::unordered_map<int, Z> map;

void test(void) {
  map.emplace(0, Z()); // error
  map[0] = Z(); // error
}

Is this possible, and if not, why not?

EDIT: Compiler is gcc 4.8.1, on Linux