Chapter 22, Problem 45GQ

Interpretation Introduction

Interpretation: For the given formula the name of the coordination compound and the optical isomers has to be determined.

Concept introduction: The transition metal atoms have tendency to form complex compounds that are linked to the certain neutral or ionic species which leads to the formation of coordination compounds. There exists a large number of coordination compounds that have a large number of applications in the chemical industry as well as in daily life.

Coordination compounds: The compounds having coordination covalent bonds which form when metal ions react with polar molecules or anions.

Ligands: The ions or molecules that forms coordination covalent bond with metal ions in a coordination compound. Ligands should have minimum one lone pair of electron, where it donates two electrons to the metal. Metal atom accepts the electron pair from a ligand forming a coordination bond.

Mono dentate ligand is ligands which donate only one pair of electrons to form bond with metal. It only makes one bond with metal. Polydentate ligand forms two or more coordination bond with metal ions to form a complex.

Oxidation number: The total number of electrons in an atom after losing or gaining electrons to make a bond with another atom. It indicates the charge of an ion.

The rule to name a coordination complex is,

1. 1. The cation is named before the anion.
2. 2. Within a complex ion, the Ligands are arranged in an alphabetical order followed by the metal ion name. The anionic Ligand should ends with a letter –o, the neutral Ligand are called by the molecules (some common name for some exception).
3. 3. When more Ligands are present, Greek prefixes like di, tri, tetra, penta, and hexa to specify their number.
4. 4. The oxidation number of the metal is represented in roman numerals immediately following the metal ion name.
5. 5. If the complex ion is an anion, the metal name should end with –ate.

$Spectrochemicalseries$ : The list of ligands arranged in an ascending order of $\text{(Δ)}$(the splitting of d-orbitals in presence of various ligands).

$\begin{array}{l}\stackrel{{}^{{\text{I}}^{\text{-}}\text{<}{\text{Br}}^{\text{-}}\text{<}{\text{SCN}}^{\text{-}}\text{<}{\text{Cl}}^{\text{-}}\text{<}{\text{S}}^{\text{2-}}\text{<}{\text{F}}^{\text{-}}\text{<}{\text{OH}}^{\text{-}}\text{<}{\text{O}}^{\text{2-}}\text{<}{\text{H}}_{\text{2}}\text{O}\text{<}{\text{NCS}}^{\text{-}}\text{<}{\text{edta}}^{\text{4-}}\text{<}{\text{NH}}_{\text{3}}\text{< en}\text{<}{\text{NO}}^{\text{2-}}\text{<}{\text{CN}}^{\text{-}}\text{<}\text{CO}}}{\to }\\ {}_{{}^{{}^{\begin{array}{l}\text{weak-field}\text{increasing(Δ)}\text{strong-field}\\ \text{ligands}\text{ligands}\end{array}}}}\end{array}$

Isomerism: Two chemical compounds are said to be isomers if they have same number and kind of atoms but different only in their orientation that is structural arrangements.

There are different types of isomerism in which geometric is of one type where the rotation around the atom is restricted like in cis-trans configuration. This is also refereed as cis-trans isomerism.

Oxidation number: It is the number that defines the number of electrons that are gained or lost by the chemical substance.