  We used multiwavelength data (HI, FUV, NUV, R) to search for evidence of star
formation in the intragroup medium of the Hickson Compact Group 100. We find
that young star-forming regions are located in the intergalactic HI clouds of
the compact group which extend to over 130 kpc away from the main galaxies. A
tidal dwarf galaxy candidate is located in the densest region of the HI tail,
61 kpc from the brightest group member and its age is estimated to be only 3.3
Myr. Fifteen other intragroup HII regions and TDG candidates are detected in
the GALEX FUV image and within a field 10'x10' encompassing the HI tail. They
have ages <200 Myr, HI masses of 10^(9.2-10.4) Msun, 0.001< SFR <0.01 Msun
yr^-1, and stellar masses 10^4.3--10^6.5 Msun. The HI clouds to which many of
them are associated have column densities about one order of magnitude lower
than N(HI)~10^21 cm^-2.
