Do you have sodium chloride molecule?

Answer 1

In the crystalline state, sodium chloride consists of sodium cations (Na+) and chloride anions (Cl-) in a regular structure in which each Na+ is surrounded by six Cl- and vice versa, so that the whole thing is electrically neutral. In the crystalline state, there are no covalently bonded 'NaCl molecules'. Similarly, when salt is dissolved in water, the ionic crystalline structure breaks down and the individual ions are surrounded by water molecules.

The interesting aspect to the question is what is the state of play in the gas phase. Astronomers are interested in this because, recently, sodium chloride has been detected in space above Saturn's moon Enceladus, and they refer to the presence of 'sodium chloride molecules'. Most chemists would disagree with this, preferring instead to talk about discrete 'ion pairs' ie Na+Cl- which are known to exist in the vapour phase. Talking about 'sodium chloride molecules' implies the existence of covalent bonding (ie electron sharing) between the sodium and chlorine atoms, and this is thought to be very improbable in the chemistry of these elements.