Formation of ultracold fermionic NaLi Feshbach molecules

We describe the formation of fermionic NaLi Feshbach molecules from an ultracold mixture of bosonic Na-23 and fermionic Li-6. Precise magnetic field sweeps across a narrow Feshbach resonance at 745 G result in a molecule conversion fraction of 5% for our experimental densities and temperatures, corresponding to a molecule number of 5 x 10(4). The observed molecular decay lifetime is 1.3 ms after removing free Li and Na atoms from the trap. Due to its extremely low reactivity, NaLi molecules in the ground state will have a much longer lifetime than KRb.