Structure of Ni(CO)4
Ni(CO)4, also known as tetracarbonyl nickel, is a coordination complex with a nickel atom at the center surrounded by four carbon monoxide ligands. Let's dive into the structure of Ni(CO)4 in detail:

Central Nickel Atom
- The central nickel atom in Ni(CO)4 has a coordination number of 4, meaning it forms bonds with four ligands.
- Nickel in Ni(CO)4 follows the 18-electron rule, where the total number of electrons from ligands and the metal center equals 18.

Carbon Monoxide Ligands
- There are four carbon monoxide (CO) ligands attached to the nickel atom in a square planar arrangement.
- Carbon monoxide ligands act as strong π-acceptor ligands, forming strong bonds with the nickel atom.

Overall Structure
- The structure of Ni(CO)4 can be visualized as a square planar geometry with the nickel atom at the center and four CO ligands surrounding it.
- The bond angles in Ni(CO)4 are approximately 90 degrees, reflecting the square planar geometry.

Properties
- Ni(CO)4 is a colorless liquid at room temperature and is highly toxic due to the presence of carbon monoxide ligands.
- It is used in organic synthesis as a catalyst for carbonylation reactions.
In conclusion, the structure of Ni(CO)4 consists of a central nickel atom coordinated with four carbon monoxide ligands in a square planar geometry, following the 18-electron rule. This complex plays a significant role in various chemical reactions and catalytic processes.