[NiCl_2(PPh_3)_2] is named as:

The correct answer is Option (2) → Dichloridobis(triphenylphosphine)nickel(II)

IUPAC rules for a neutral complex:

• Ligands are named first, in alphabetical order: chlorido (\( \ce{Cl^{-}} \)) before triphenylphosphine (\( \ce{PPh3} \)).

• Two chlorido ligands take the prefix di. Because the name triphenylphosphine already contains a numerical prefix (tri), two of them are shown by bis with the ligand in parentheses: bis(triphenylphosphine).

• Oxidation state of Ni: x + 2(−1) + 2(0) = 0, so x = +2, written as nickel(II). The complex is neutral, so the metal keeps its plain name.

Why the other options are incorrect

• Option (1) …nickel(III) — Incorrect. With two \( \ce{Cl^{-}} \) and two neutral \( \ce{PPh3} \) ligands in a neutral complex, nickel is +2, not +3.

• Option (3) Nickeldichlorotriphenylphorphorus(II) — Incorrect. The metal must be named after the ligands, bis is missing for the two phosphine ligands, and the ligand is triphenylphosphine, not “phosphorus”.

• Option (4) Triphenylphosphinenickelate (II) phosphate — Incorrect. The complex is neutral, so the ending “-ate” (used for anionic complexes) is wrong, the chlorido ligands are missing and there is no phosphate ion.

NCERT (2026-27 edition):
Naming of Mononuclear Coordination Compounds – “… When the names of the ligands include a numerical prefix, then the terms, bis, tris, tetrakis are used, the ligand to which they refer being placed in parentheses. For example, [NiCl₂(PPh₃)₂] is named as dichloridobis(triphenylphosphine)nickel(II).”

Note: The same/similar question has been asked in different years by NTA as per the details given below: