Question

Which of the following terms is/are used to indicate the number of individual ligands that include a numerical prefix in the name of a coordination compound?

• A. tetra
• B. penta
• C. tris
• D. tetrakis

Answer 1

Answer: (C), (D)

tetrakis

The terms bis, tris, tetrakis are used when the names of the ligand include a numerical prefix. Else, the prefixes used are mono, di, tri, tetra etc.
If there are several ligands of the same type, the prefixes like di, tri, tetra, penta, etc., are used to indicate the number of ligands of that type.
For example, $\left[Co\right(N{H}_3{)}_6]C{l}_3$ is named Hexaamminecobalt (III) chloride.
If the ligand is complex and is repeated two, three or four times, then the word bis, tris, tetrakis, etc., are used.
For example, $\left[Co\right(en{)}_3]C{l}_3$ is named Tris-(ethane–1,2–diamine)cobalt (III) chloride