The matrix isolation technique has been combined with infrared spectroscopy to identify and characterize the product of the codeposition of CH 3 ReO 3 with NH 3 into inert matrices at 14 K. This codeposition led to the formation of the isolated 1:1 complex between these two reagents and its isolation in argon and nitrogen matrices. The complex is characterized by perturbations to all of the vibrational modes of the NH 3 subunit in the complex, including a large, 185 cm - 1 blue shift of ν 2 , the symmetric deformation mode. In addition, shifts of the ReO 3 antisymmetric stretch and ReO 3 symmetric bending of the CH 3 ReO 3 subunit in the complex were observed. This complex, while predicted theoretically, has not been reported previously.