We observed for the first time the thermally stable point positron-sensitive center of a vacancy type in n-FZ-Si (P) material irradiated at RT by ~ 0.9-MeV electrons. The center that emerges after isochronal annealing at Tanneal. 260 ? 280 oC is found to be similar to the vacancy-group-V-atom complex revealed in the same Si material irradiated by 15-MeV protons; the detecting of the centers by the positron trapping is finalized at Tanneal. 520 oC. The annihilation gamma-quanta to be emitted from the positron trap gives rise to a characteristic positron lifetime tau2 (I2 ~ 38 - 19 %) <= 276 - 294 ps which is somewhat longer than the one predicted for unrelaxed single vacancy tauV 254 - 261 ps. Our data suggested a configuration of the complex VopPVop, wherein the atom of phosphorus is tied to a split open vacancy volume 2Vop. It is argued that Vop volume detected by the positron trapping may be formed by extended semi-vacancy, Vs-ext, or by the relaxed inwards vacancy, Vinw, thus resulting in a distorted Vs-extPVs-ext or VinwPVinw configurations.