The solution of $TiCl_4$ and trialkylaluminium used as a catalyst in the polymerization of olefins is known as.....

The correct pair of orbitals involved in $\pi$-bonding between metal and $CO$ in metal carbonyl complexes is

$CH_3MgI$ is an organometallic compound due to the presence of:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: The metal-carbon bond in metal carbonyls possesses both $\sigma$ and $\pi$ character.
Reason $(R)$: The ligand-to-metal bond is a $\sigma$ bond and metal-to-ligand bond is a $\pi$ bond.
In the light of the above statements,choose the most appropriate answer from the options given below :

The correct statement$(s)$ regarding the binary transition metal carbonyl compounds is (are) (Atomic numbers: $Fe = 26, Ni = 28$)
$A$. Total number of valence shell electrons at metal centre in $Fe(CO)_5$ or $Ni(CO)_4$ is $16$
$B$. These are predominantly low spin in nature
$C$. Metal-carbon bond strengthens when the oxidation state of the metal is lowered
$D$. The carbonyl $C-O$ bond weakens when the oxidation state of the metal is increased

In the synergic bond of metal carbonyls,which of the following orbitals is involved?