Herein, we report the catalytic-free acoustic shock wave-induced synthesis of the non-stoichiometry compound of sodium chloride (Na₃Cl₂-P4/m) from the stoichiometry NaCl (B1). The shocked NaCl crystal structure is formed as a mixed phase together with the NaCl (B1) and (Na₃Cl₂-P4/m) thereby the formation of non-stoichiometry compound of Na₃Cl₂ is confirmed by the diffraction, vibrational, spectroscopic and microscopic techniques. X-ray photoelectron spectroscopic study reveals the positive energy shift of Na 1 s peak which confirms the formation of higher coordination number Na₃Cl₂ (six to eight) such that it can be considered as Na rich structure. The typical cubic morphology has changed into butterfly wing structure under shocked conditions which is found to be novel, to date. Due to the formation of Na-rich crystal structure, the electrical properties of the shocked crystal are greatly altered. The maximum values of the real part of the impedance of the control and shocked crystals are 1.9 × 10⁷ ohm and 1.0 × 10⁷ ohm, respectively at the lower frequency regions. The present study offers a new platform to synthesize the stable non-stoichiometry NaCl structures under ambient conditions by low pressure acoustic shock waves which could bring about new understanding and implications on NaCl crystals and their applications.