Coordination Compounds Test - 5

A double salt is a salt which crystallises as a single substance but when it is dissolved it gets ionised as two salts and loses its identity in solution.KCl.MgCl₂.6H₂O is double salt.

Oxalate is a bidentate ligand. So it is a chelate ligand and gives chelate complexes.

The central metal atom/ion behaves as a Lewis acid while the ligand acts as a lewis base. The ligand can be a negatively charged ion or a neutral molecule which donates its electron pair to the central metal atom/ion which acts as an electron pair acceptor (Lewis acid).

C₅H₅^- is cyclopentadienyl anion and it is a negatively charged ligand.

In the nomenclature of coordination compounds the ligands are named first followed by the name of central metal atom/ion followed by the oxidation state of the metal in parenthesis. Here CO is the carbonyl ligand, there are 12 CO ligands and they are attached to 3 Mn i.e. Manganese metal atoms. CO is a neutral ligand and carries no charge and hence the oxidation state of Mn is 0. So the IUPAC name is Dodecacarbonyltrimanaganese(0).

Cis-platin ( cis – [Pt(NH₃)₂(Cl)₂] ) is a coordination compounds used in treatment of cancer. It inhibits the growth of tumors.

C₅H₅^- is cyclopentadienyl ligand. Name of ligand is written first followed by the name of the central metal and its oxidation state in parenthesis in roman numerals. C₅H₅^- carries -1 charge and there are two such ligands. The overall charge on the complex is 0 so to balance the -2 charge of the ligands iron must be in +2 oxidation state. Hence, the IUPAC name of the complex is Bis(cyclopentandienyl)iron(II).

Ti has atomic number 22. And its electronic configuration is 1s²2s²2p⁶3s²3p⁶4s²3d².

In given complex, there are four NO₃^{​​​​-} groups bonded to Ti. Each NO_{​​​​​3}^{​​​​-} carries -1 charge, hence there is -4 charge on the ligands and overall the complex is neutral which means Ti is in +4 oxidation state. So Ti^{​​​​​4+} has an electronic configuration 1s²2s²2p⁶3s²3p⁶ means there are no electrons in d orbital and hence d-d transition is not possible. So it is expected to be colourless.

In an ionic compound cation is named first and then the anion. When the complex is anion we add -ate to the central metal. Here the cation is Potassium K⁺ and the anion is the complex. There are 2 K⁺ and hence a total of +2 charge which is balanced by -2 charge on the complex. OH ^- is hydroxido ligand. Ligand is named first followed by the name of the central metal atom/ion with its oxidation state in paranthesis in roman numerals. Here there are 4 OH ^- and each carries a -1 charge. Let the oxidation state of Zn be x. Then

x + 4(-1) = -2
x - 4 = -2
x = -2 + 4 = +2
So, oxidation state of Zn=+2
So, the IUPAC name is Potassium tetrahydroxidozincate(II).