[methic]

Greetings, all.

So, my book refers to Ammonium nitrate as an Ionic Compound. It also says that ionic bonds are defined as being between metals and nonmetals. I understand that both ammonium and nitrate are polyatomic ions and why they're connected (+ and -); however, the part that trips me up is that neither of them are metals.

NH₄^- and NO₃^-

Are ionic compounds not exclusive to metal + nonmetal relationships, then? Is this some sort of single exception to the rule (which I notice a lot of in chemistry!  ). Wait! Also, while I'm here. Is hydrogen a metal or nonmetal? It's listed in group I as a metal, but it also has covalent relationships in other compounds. My book says covalent bonds are only between nonmetals (electron sharing). Does this mean that no metallic element can form covalent relationships with other elements (which brings me back to hydrogen!)?

Regards,

methic 

[opti384]

The definition of ionic bonds are not bonds formed between a metal ion and a nonmetal ion. Rather it's the bond between cations and anions as in the example you gave--ammonium nitrate. I think people sometimes mistaken that an ionic bond should always accompany both metal ions and nonmetal ions. That's probably because most ionic compounds consist of those of metal ions and nonmetal ions.

Also, hydrogen is not a metal ion. Though it is positioned on the group of alkaline metals, it's a nonmental element.

[408]

.

Also, hydrogen is not a metal ion. Though it is positioned on the group of alkaline metals, it's a nonmental element.

hydrogen can be a metal sometimes...
http://en.wikipedia.org/wiki/Metallic_hydrogen