Can Ion­ic Com­pounds Exist as Sol­id, Liq­uid and Gas ?

But first things first… 

What are Ion­ic Compounds ?

Ion­ic com­pounds are com­pounds that are com­posed of oppo­site­ly charged ions, anions and cations. The force which holds the two ions (charged atoms) togeth­er is called the elec­tro­sta­t­ic force, and the bond that exists between them is called an ion­ic bond. In an ion­ic com­pound, there are mil­lions of ions present and all these ions are held togeth­er by elec­tro­sta­t­ic forces. These forces are very strong, hold­ing ions firm­ly in place and thus form­ing a crys­tal lat­tice struc­ture. At nor­mal room tem­per­a­ture, the strength of an ion­ic bond is much greater than the indi­vid­ual kinet­ic ener­gy of the two ions par­tic­i­pat­ing in the bond. Hence, ion­ic com­pounds exist only as sol­id under nor­mal con­di­tions. This begs the ques­tion : If the con­di­tions are to be changed, can ion­ic com­pounds exist as liq­uids and/​or gas ?

Can Ion­ic Com­pounds Exist as Liq­uid Under Cer­tain Defined Conditions ?

Yes. An ion­ic com­pound if dis­solved in water or melt­ed can exist as liq­uid as well. Exam­ples include NaCl (salt) dis­solved in water, molten elec­trolyte­found in fuel cells. How­ev­er, it’s impor­tant to note that in order to melt an ion­ic com­pound you would need tremen­dous amount of heat ener­gy : NaCl melts at 801°C and MgO has a melt­ing point of 2850°C.

Can Ion­ic Com­pounds Exist as Liq­uid Under Cer­tain Defined Conditions ?

Yes, it may. Because if melt­ing an ion­ic com­pound requires extreme tem­per­a­ture, to vapor­ize it you will need superla­tive amount of heat ener­gy. This is not pos­si­ble to attain for every ion­ic com­pound with­out caus­ing a dis­in­te­gra­tion of the con­trolled envi­ron­ment. Hence why, we used the word ​“may”. For exam­ple, to vapor­ize NaCl you will need to heat the com­pound at a tem­per­a­ture of 1413°C. Sim­i­lar­ly, to con­vert MgO to gaseous state, you will have to go beyond 3600°C in heat­ing tem­per­a­ture. One ques­tion that comes to mind is, since ion­ic com­pounds do not com­pose of dis­crete mol­e­cules (they are made of charged atoms), after vapor­iza­tion, would they still exist in the form of com­pound ? Shouldn’t they turn into mix­ture of indi­vid­ual atom­ized gas­es ? The answer is no. Even after vapor­iza­tion, ion­ic com­pounds do retain­ing some oftheir com­pound ori­ent­ed prop­er­ties, exist­ing as monomers and dimers. So, there you have it – ion­ic com­pounds can exist as sol­id, liq­uid and gas depend­ing on the con­di­tions they are exposed to. A BONUS read : Every­thing you need to know about ion­ic liquids