Write the Lewis structure for each of the following species, describe its geometry, and indicate the oxidation state of the nitrogen:
(a) \(\mathrm{HNO}_{2}\),
(b) \(\mathrm{N}_{3}^{-}\),
(c) \(\mathrm{N}_{2} \mathrm{H}_{5}^{+}\),
(d) \(\mathrm{NO}_{3}^{-}\).
Text Transcription:
HNO2
N3 -
N2H5 +
NO3 -
Step 1 of 5) In general, the complexes formed by chelating ligands (that is, bidentate and polydentate ligands) are more stable than the complexes formed by related monodentate ligands. The equilibrium formation constants for 3Ni(NH3)642+ and 3Ni(en)342+ illustrate this observation:Although the donor atom is nitrogen in both instances, 3Ni(en)342+ has a formation constant that is more than 108 times larger than that of 3Ni(NH3)642+. This trend of generally larger formation constants for bidentate and polydentate ligands, known as the chelate effect, is examined in the “A Closer Look” essay on page 1001. Chelating agents are often used to prevent one or more of the customary reactions of a metal ion without removing the ion from solution. For example, a metal ion that interferes with a chemical analysis can often be complexed and its interference thereby removed. In a sense, the chelating agent hides the metal ion. For this reason, scientists sometimes refer to these ligands as sequestering agents. Phosphate ligands, such as sodium tripolyphosphate, Na53OPO2OPO2OPO34, are used to sequester Ca2+ and Mg2+ ions in hard water so that these ions cannot interfere with the action of soap or detergents.
