Write down three characteristics of ironic bond?
Answers
They have high melting points and high boiling points. ...
They have higher enthalpies of fusion and vaporization than molecular compounds. ...
They're hard and brittle. ...
They conduct electricity when they are dissolved in water. ...
They're good insulators.
Answer:
First, compounds with ionic bonds are not necessarily soluble in water. Barium sulphate comes to mind. My view is the bond is ionic in the solid state when the binding is that of a three dimensional matrix of entities that are held together by electrostatic energy and where, in the structure you cannot isolate specific molecules. That sounds clumsy, but I can't think of something better right now. Thus in a crystal of sodium chloride you cannot assign a specific chlorine atom to any given sodium atom. There is no sodium chloride molecule, but rather a stack of sodium and chloride ions and the structure is determined by how close such collection can pack, and not by specific sodium-chloride bonds.
If they dissolve in some fluid, the solution will conduct electricity and specific cations and anions will be deposited at the cathode and anode, although they may well react immediately. Thus electrolysing a sodium salt gives hydrogen, not sodium, from an aqueous solution. Properties like melting point are not indicative, as there are ionic liquids that are made totally from carbon, nitrogen, oxygen and hydrogen, while carbon has a melting point in the vicinity of 3,500 degrees C.