The reaction of NiBr2 with two equivalents of PPh3 in CS2 at –78 °C gives a red-coloured diamagnetic complex, [NiBr2 (PPh3)2 ]. This transforms to a green-coloured paramagnetic complex with the same molecular formula at 25 °C. The geometry and the number of unpaired electrons in the green-coloured complex, respectively, are:

The reaction of NiBr2 with two equivalents of PPh3 in CS2 at –78 °C

1.	The reaction of NiBr2 with two equivalents of PPh3 in CS2 at –78 °C gives a red-coloured diamagnetic complex, [NiBr2 (PPh3)2 ]. This transforms to a green-coloured paramagnetic complex with the same molecular formula at 25 °C. The geometry and the number of unpaired electrons in the green-coloured complex, respectively, are:
A.	tetrahedral and 1
B.	tetrahedral and 2
C.	square planar and 2
D.	square planar and 4
Answer» C. square planar and 2