Ammonium hydroxide does not exist - Journal of Chemical Education

No matter how the s and three p orbitals are hybridized, nitrogen can form a maximum of only four bonds. Keywords (Audience):. First-Year Undergraduat...
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Ammonium Hydroxide Does Not Exist Nitrogen has only four orbitals in its valence shell. No matter how the sand three p orbitals are hybridized, nitrogen can farm a maximum of anlv four bonds. If NHIOH existed. it would have to be 1005%ionized NHatOH-. Tetramethvlam. monium hydroxide does exist and is as strong a haae as sodium hydroxide. Phosphmuscan use theempty d orbitals in its valenceahell and makeapeeies that have nonitrogen equivalent,~uehsa phosphorus pentachloride and the hexafluomphosphate ion. Similarly s phosphine oxide can he written RIP=O, while an m i n e oxide is limited to R3N+-0-. Since both ammonia and water are polar and engage in hydrogen bonding, it is not surprising that they interact with each other. There are low-melting, solid hydrates of ammonia. In liquid aqueous ammonia, nuclear magnetic resonance studies have shown that the lifetime of a HzO ... . NH3 diffusion-controlled collision contact is about 10WQs. We should not mislead our students by writing ~

NH,OH(aq)

6

NH,'

~

+ OH-

but should always write NH,(aq)

+ H,O ==NH,' + OH-

Similarly, we should prevail on laboratory supply houses to stop labelling their bottles "ammonium hydroxide". It doesn't exist.

John Yoke Oregon State Unlverslty Cowallis. OR 97331

310

Journal of Chemical Education