When fullerenes 60 capture an alkali metal M − C_60 , they acquire a powerful permanent dipole. This suggests that if the system is in an inert atmosphere, like Argon, they tend to form dimers (M − C_60)2 , producing a gas whose thermodynamical properties can be studied. On this work, we focus on the degrees of freedom that appear when the dimer has formed. The fraction of ( M − C_60)2 that can be created is calculated by using the standard physical statistics and can be graphed against the temperature on the 273.15 K and 373.15 K interval.