The ultradispersed tetragonal titanium dihydride (specific surface of 10-55 m(2)/g, the average size of particles of 15-40 nm), stabilized by 0.1-0.15 atom of nitrogen per molecule of the titanium dihydride, was prepared by an interaction of the titanium powder with ammonia under a pressure of 0.7-0.8 MPa in a presence of the ammonium chloride. The influence of a size of the particles of the initial titanium powder (10-100 mcm) and a temperature (200-400 degrees C) on a direction of an interaction and on a state (microcrystalline or ultradispersed) of the titanium dihydride was investigated. It has been established that the derived titanium dihydride crystallizes into a tetragonal lattice with the constants a(o) = 4.468 Angstrom, c(o) = 4.391 Angstrom and is resistant in an inert atmosphere to 600 degrees C.