Computational thermochemistry and a structure for gaseous phase NaCl3

Abstract Thermodynamically stable cubic and orthorhombic NaCl₃ as well as NaCl₇ have been synthesized [1]. A thermochemical explanation was recently propose [2] for the stability of such unusual compounds [2]. In the present work, molecular modeling (SE-PM3/MMFF) of a dimmeric structure for NaCl₃is performed. The calculated cation and anion charges, as well as bond distances for the NaCl₃ gaseous dimmer are in good agreement with values for the solid Pm3nNaCl₃ [1]. To the modelled dimmer Δ_f^gH^θ= -196.4 kJmol^-1.For such dimmeric compound: point group C₁; dNa-Na = 273.3 pm; dNa-Cl = 246.8-248.1pm; ZPE 10.01 kJmol^-1; H^θ= -154.5 kJmol^-1; G^θ = -289.3kJmol^-1, S^θ = 425.1JK^-1mol^-1; C_v = 169.6JK^-1mol^-1).

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