  The shell of the classical nova V5668 Sgr was resolved by ALMA at the
frequency of 230 GHz 927 days after eruption, showing that most of the
continuum bremsstrahlung emission originates in clumps with diameter smaller
than $10^{15}$ cm. Using VLA radio observations, obtained between days 2 and
1744 after eruption, at frequencies between 1 and 35 GHz, we modeled the nova
spectra, assuming first that the shell is formed by a fixed number of identical
clumps, and afterwards with the clumps having a power law distribution of
sizes, and were able to obtain the clump's physical parameters (radius, density
and temperature). We found that the density of the clumps decreases linearly
with the increase of the shell's volume, which is compatible with the existence
of a second media, hotter and thinner, in pressure equilibrium with the clumps.
We show that this thinner media could be responsible for the emission of the
hard X-rays observed at the early times of the nova eruption, and that the
clump's temperature evolution follows that of the super-soft X-ray luminosity.
We propose that the clumps were formed in the radiative shock produced by the
collision of the fast wind of the white dwarf after eruption, with the slower
velocity of the thermonuclear ejecta. From the total mass of the clumps, the
observed expansion velocity and thermonuclear explosion models, we obtained an
approximate value of 1.25 M$_{\odot}$ for the mass of the white dwarf, a
central temperature of $10^7$ K and an accretion rate from the secondary star
of $10^{-9}-10^{-8}$ M$_{\odot}$ y$^{-1}$.
