Which of the following are paramagnetic? Choose the correct answer from the options given below :
- A and D only
- A, D and E only
- A and C only
- B and E only
Answer
(1) A and D only
Solution
A. [NiCl4]2-: Ni2+ (3d8); Cl- is a weak field ligand, so no pairing; sp3, tetrahedral → 2 unpaired electrons → paramagnetic.
B. Ni(CO)4: Ni(0), 3d and 4s electrons pair up to 3d10; sp3 → no unpaired electron → diamagnetic.
C. [Ni(CN)4]2-: CN- is a strong field ligand, the two 3d electrons pair up; dsp2, square planar → diamagnetic.
D. [Ni(H2O)6]2+: 3d8, octahedral (sp3d2) → 2 unpaired electrons → paramagnetic.
E. Ni(PPh3)4: Ni(0), 3d10, sp3 → diamagnetic.
∴ Paramagnetic: A and D only.
Answer: (1)