A polycrystalline sample of the title compound containing a small fraction of deuterium was irradiated in an infrared region containing no apparent absorption bands. Holes and antiholes were produced in the N-D stretching bands. Each irradiation thus was at the wavenumber of a combination band involving a particular N-D stretch. Most of the combinations consist of the N-D stretch of the ammonium ion together with an internal mode of the zinc complex ion.