Question

Which of the following compounds have been named correctly according to IUPAC rules:
(a)$\left[Cr\right(N{H}_3{)}_{5}C{O}_3]Cl$ - Pentamminecarbonatochromium (III) chloride
(b)$\left[Co\right(N{H}_3{)}_{5}ONO]C{l}_2$ - Pentammine-O-nitritocobalt (III) chloride
(c)$K_3\left[Cr\right(CN{)}_6]$ - Potassium hexacyanochromate(III)
(d)$\left[Co\right(N{H}_3{)}_6]C{l}_3$ - Hexamminecobalt (III) chloride

• A. a and b
• B. only c
• C. a, b and c
• D. all of the above

Answer 1

Answer: (D)

all of the above

The compounds a, b,c and d have been named correctly according to IUPAC rules:
(a)$\left[Cr\right(N{H}_3{)}_{5}C{O}_3]Cl$ - Pentamminecarbonatochromium (III)
$C{O}_3^{2-}$ is named as carbonato and not as carbonate.
There are 5 ammonia ligands and one carbonate ligand. They are named in alphabetical order.
The prefix penta is used to name 5 ammonia ligands.
The oxidation state of $Cr$ is written in parenthesis in roman numerals.
(b)$\left[Co\right(N{H}_3{)}_{5}ONO]C{l}_2$ - Pentammine-O-nitritocobalt (III) chloride;
There are 5 ammonia ligands and one nitrito ligand. They are named in alphabetical order.
The prefix penta is used to name 5 ammonia ligands.
The oxidation state of $Co$ is written in parenthesis in roman numerals.
(c)$K_3\left[Cr\right(CN{)}_6]$ - Potassium hexacyanochromate(III)
There are 6 cyano ligands.
The prefix six is used to name 6 cyano ligands.
The oxidation state of $Cr$ is written in parenthesis in roman numerals.
(d)$\left[Co\right(N{H}_3{)}_6]C{l}_3$ - Hexamminecobalt (III) chloride
There are 6 ammonia ligands.
The prefix six is used to name 6 ammonia ligands.
The oxidation state of $Co$ is written in parenthesis in roman numerals.