四、 Summary
Our study conclusions can be summarized as follows:
1. Benchmark calculations show that
our theoretical results on the spectroscopic constants of are in good
agreement with previous theoretical and experimental findings. Our
predictions that the salt compound
may exist at temperatures lower than −28.39 °C are consistent with the
observation that it can be prepared at −40 °C. Our predicted individual
ion volumes of the AuXe42+ cation,
which are used to estimate lattice energies are in good agreement with
the experimental values. The validity of the theoretical calculation
methods in the benchmark calculations demonstrated above ensures that
our calculation results in this article are reliable.
2. Our calculations show that the corresponding enthalpy change ∆H(2)
for
MAr42+(Sb2F11−1)2(M=Au,Ag,Cu) could be estimated to
be <−15.477, −49.332, and −74.508 kcal/mol, respectively,
according to the Born–Haber cycle.
MAr42+(Sb2F11−1)2(M=Au,Ag,Cu) salt compounds can be synthesized, and their upper-limit
stable temperatures are estimated to be −224.43, −146.21, and −80.39 °C,
respectively. The bulk salt compound
CuAr42+(Sb2F11−1)2is the most promising candidate for synthesis due to Cu having the
largest binding energy with Ar and the smallest ionic radius among the
MAr42+(M=Ag,Cu,Au) systems.
3.Our calculations also show that the outlook for synthesizing the salt
compounds is obscure.
4. Accurate predictions of the stability of ionic salt compounds should
be based on rigorous Born–Haber cycles, and the starting material of
the cycles must be stable.