Nibr, reacts with (et)(ph,) pat -78°c in cs, to give red compound 'a, which upon standing at room temperature turns green to give compound, b' ofthe same formul

NiBr, reacts with (Et)(Ph,) Pat -78°C in CS, to give red compound 'A, which upon standing at room temperature turns green to give compound, B' ofthe same formula. The measured magnetic momen of A'and B'are 0.0 and 3.2 BM, respectively. The geometries of A' and "B are (a) square planar and tetrahedral (c) square planar and octahedral (b) tetrahedral and square planar (d) tetrahedral and octahedral Stabiliatis