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Ziegler catalyst $\to$ Titanium

Ziegler- Natta catalyst contains two parts – a transition metal compound and an organoaluminum compound. Organoaluminum compounds contain bonds between aluminum and carbon atoms. Examples of Ziegler-Natta catalysts include ${TiCl}_{4} + {Et}_{3}Al and {TiCl}_{3} + {AlEt}_{2}Cl$. So, if we want to write the chemical formula of one of the Ziegler-Natta catalysts then it can be represented as ${TiCl}_{4}Al ( {CH}_{3}{)}_{2} ( {CH}_{2}{)}_{2}Cl$.

Blood pigment $\to$Iron

Haemoglobin: RBCs/erythrocytes play an important role in the transport of oxygen to various tissues. It is mainly due to the presence of an iron-containing, red-colored pigment called haemoglobin. The presence of haemoglobin gives RBCs the red colour.

Wilkinson catalyst$\to$Rhodium

Wilkinson's catalyst is usually obtained by treating rhodium\left(III\right)$chloride hydrate with an excess of triphenylphosphine in refluxing ethanol. Triphenylphosphine serves as both a ligand and a two-electron reducing agent that oxidises itself from oxidation state$\left(III\right)$to\left(V\right)$.

Vitamin ${B}_{12} \to$Cobalt

Cobalt is a major part of the structure of vitamin $B12$. Therefore, if you get enough vitamin $B12$, you will also get enough cobalt. Adults need about $0 . 0015mg$ ($1 . 5$ micrograms) of vitamin $B12$ a day.