<p>This study examines the phase formation process of a novel antimony-containing pyrochlore (space group <i>Fd-</i>3<i>m</i>) Bi_2.7Zn_0.46Ni_0.70Sb₂O_10+∆. The solid-state synthesis of this pyrochlore using oxide precursors is a complex, multi-stage process. The active interaction of the oxide precursors commences at temperatures exceeding 600°C, leading to the formation of an initial intermediate phase, Bi₃SbO₇. Individual oxide precursors, including bismuth trioxide and antimony tri- and pentoxides, are present in the sample up to 750°C. At temperatures above this threshold, a stable cubic phase, Bi₃M_2/3Sb_7/3O₁₁ (space group <i>Pn</i>-3), is formed, which remains stable up to 900°C. The pyrochlore phase first emerges in the sample at 650°C, with a substantial increase in its proportion observed at temperatures above 850°C. The formation of a pure pyrochlore phase occurs within the temperature range of 950 – 1050°C. The sintering of fine-grained ceramic is carried out at 1050°C. The obtained microstructure is characterized by low porosity, which is attributed to the coalescence of small grains into larger crystallites with a longitudinal size of 2 – 4 μm. The unit cell parameter of the pyrochlore varies unsteadily within the temperature range of 650 – 1050°C, reaching a minimum value of 10.464 Å at 800°C. The lattice parameter of the pure pyrochlore phase Bi_2.7Zn_0.46Ni_0.70Sb₂O_10+∆ is 10.474 Å.</p>