Is it a ionic or a covalent bond?

[jaumzaum]

In the compunds below, are the bonds most ionic or covalent?

CH3-Mg-Cl (Grignard reagent), C-Mg bond

[Ag(NH3)2]+ (Tollens' reagent), Ag-N bond

Thanks
John

 

[Seydlitz]

For the Grignard reagent bond, C-Mg, I think it is covalent mostly. The electronegativity difference between C-Mg is not too significant. But it will be polar certainly.

For the Tollen's reagent, the bond between NH3 and Ag+ is that of dative covalent, because NH3 can be considered as ligand to Ag+

 

[DanL]

For the Grignard reagent, the Mg-Cl bond is covalent, but the Mg-CH3 bond is ionic with the carbon carrying the negative charge and the Mg-Cl carrying the positive charge. This allows the lone pair on the carbanion to attack sites on other molecules containing a partial positive (such as carbonyls).