  We use the 13CO(2-1) emission from the SEDIGISM high-resolution spectral-line
survey of the inner Galaxy, to extract the molecular cloud population with a
large dynamic range in spatial scales, using the SCIMES algorithm. This work
compiles a cloud catalogue with a total of 10663 molecular clouds, 10300 of
which we were able to assign distances and compute physical properties. We
study some of the global properties of clouds using a science sample,
consisting of 6664 well resolved sources and for which the distance estimates
are reliable. In particular, we compare the scaling relations retrieved from
SEDIGISM to those of other surveys, and we explore the properties of clouds
with and without high-mass star formation. Our results suggest that there is no
single global property of a cloud that determines its ability to form massive
stars, although we find combined trends of increasing mass, size, surface
density and velocity dispersion for the sub-sample of clouds with ongoing
high-mass star formation. We then isolate the most extreme clouds in the
SEDIGISM sample (i.e. clouds in the tails of the distributions) to look at
their overall Galactic distribution, in search for hints of environmental
effects. We find that, for most properties, the Galactic distribution of the
most extreme clouds is only marginally different to that of the global cloud
population. The Galactic distribution of the largest clouds, the turbulent
clouds and the high-mass star-forming clouds are those that deviate most
significantly from the global cloud population. We also find that the least
dynamically active clouds (with low velocity dispersion or low virial
parameter) are situated further afield, mostly in the least populated areas.
However, we suspect that part of these trends may be affected by some
observational biases, and thus require further follow up work in order to be
confirmed.
