Question

A coordination compound has the formula \[\ce{CoCl3.4NH3}\]. It precipitates silver ions as AgCl and its molar conductance corresponds to a total of two ions.

Based on this information, answer the following question:

1. Deduce the structural formula of the complex compound.
2. Write the IUPAC name of the complex compound.
3. Draw the geometrical isomers of the complex compound.

Answer 1

(a) Because just one AgCl is created, only one chloride ion is precipitated, which equals one negative ion. As a result, the structural formula for the complex will be.
\[\ce{[Co(NH3)4Cl2]Cl}\]

(b) IUPAC name: tetraamminedichloridocobalt (Ill) chloride

(c) Geometrical isomers

\[\begin{array}{cc}
\phantom{..........}\ce{H3N\phantom{....}NH3\phantom{....}Cl\phantom{........}H3N\phantom{....}NH3\phantom{....}Cl\phantom{.........}H3N\phantom{....}Cl\phantom{....}NH3}\phantom{....}\\
\phantom{......}\backslash\phantom{.....}|\phantom{.....}/\phantom{..............}\backslash\phantom{.....}|\phantom{.....}/\phantom{..............}\backslash\phantom{.....}|\phantom{.....}/\phantom{}\\
\phantom{.........}\ce{Co\phantom{........................}Co\phantom{.......................}Co}\phantom{..}\\
\phantom{......}/\phantom{.....}|\phantom{.....}\backslash\phantom{..............}/\phantom{.....}|\phantom{.....}\backslash\phantom{..............}/\phantom{.....}|\phantom{.....}\backslash\phantom{}\\
\phantom{.........}\ce{H3N\phantom{.....}NH3\phantom{....}Cl\phantom{.........}Cl\phantom{.....}NH3\phantom{....}H3N\phantom{........}H3N\phantom{...}NH3\phantom{...}Cl}\phantom{.....}
\end{array}\]