Ammonium pertechnetate is a chemical compound with the formula NH<sub>4</sub>TcO<sub>4</sub>. It is the ammonium salt of pertechnetic acid. The most common form uses <sup>99</sup>Tc. The compound is readily soluble in aqueous solutions forming ammonium and pertechnetate ions.
It can be synthesized by the reaction of pertechnetic acid and ammonium nitrate:
It thermally decomposes under inert atmosphere at 700 ðC to technetium dioxide:
Passing hydrogen sulfide through acidic solutions of ammonium pertechnetate produces Technetium(VII) sulfide: