The reaction of $\mathrm{NiBr}_{2}$ with two equivalents of $\mathrm{PPh}_{3}$ in $\mathrm{CS}_{2}$ at $-78^{\circ} \mathrm{C}$ gives a red-colored diamagnetic complex. $\left[\mathrm{NiBr}_{2}\left(\mathrm{PPh}_{3}\right)_{2}\right]$. This transforms to a green-colored paramagnetic complex with the same molecular formula at $25^{\circ} \mathrm{C}$. The geometry and the number of unpaired electrons in the green-colored complex, respectively, are: