Lead magnesium niobate Pb(Mgl/gNb2/9)O 9 (designated as PMN) with perovskite structure has recently been considered as important in the area of electronic ceramics because of its high dielectric constant with flat temperature dependence. To obtain the desired perovskite PMN, it was concluded [1] that the intermediate pyrochlore phase(s) formation must be eliminated. To achieve this, the Columbite precursor method [1,2] is generally employed where MgO and Nb205 are pre-reacted to form the Columbite MgNb206 (designated as MN) followed by its reaction with PbO to form the perovskite PMN. However, Shrout et al. [1, 2] observed that the Columbite precursor method can yield 95% perovskite phase, and to obtain 100% perovskite phase (as detected by X-ray), excess MgO has to be added. On the other hand, Lejeune and Boilet [3] have been able to synthesize 100% perovskite phase by adding excess PbO. Horowitz [4] also reported that up to 94% perovskite phase can be obtained by the Columbite precursor method without using any additive. It is to be noted that [5] excess PbO and MgO are responsible for lowering and ageing the dielectric properties of PMN. Incidentally, Shrout et al. [1, 2] and Horowitz [4] reported the formation of MN by reacting MgO and Nb205 at around 1000 °C, whereas, McCarthy [6] mentioned 1200 °C as the calcination temperature to obtain phase-pure MN. Here we report the formation behaviour of MN for two different solid-state reaction routes and show that if phase-pure precursor MN can initially be formed by a proper calcination schedule, 100% perovskite PMN phase can be obtained without the use of any additive. The raw materials used for synthesis were magnesium hydroxycarbonate (E. Merck, Germany), Nb205 (E. Merck, Germany), magnesium metal powder (S. D. Fine, India) and niobium metal powder (E. Merck, Germany). In the first route (designated as batch A), magnesium hydroxycarbonate and niobium pentoxide were used as raw materials, and in the second route (designated as batch B), magnesium metal powder and niobium metal powders were used. The raw materials were mixed in an agate mortar and pestle under acetone. Initial calcinations were done at 900 °C for 20 h for both A and B batches. These calcined materials were recalcined at different temperatures and the schedules are depicted in Table I. X-ray diffraction studies were carried out with a Philips PW 1730 diffractometer using CuKo~ radiation. Fig. 1 depicts some of the representative X-ray