Loose groups of galaxies in the Las Campanas Redshift Survey

A "friends-of-friends" percolation algorithm has been used to extract a cat alog of deltan/n = 80 density enhancements (groups) from the six slices of the Las Campanas Redshift Survey (LCRS). The full catalog contains 1495 gro ups and includes 35% of the LCRS galaxy sample. A clean sample of 394 group s has been derived by culling groups from the full sample that either are t oo close to a slice edge, have a crossing time greater than a Hubble time, have a corrected velocity dispersion of zero, or contain a 55 " "orphan" (a galaxy with a mock redshift that was excluded from the original LCRS redsh ift catalog due to its proximity to another galaxy-i.e., within 55 "). Medi an properties derived from the clean sample include a line-of-sight velocit y dispersion sigma (los) = 164 km s(-1), crossing time t(cr), = 0.10 H-0(-1 ), harmonic radius R-h = 0.58 h(-1) Mpc, pairwise separation R-p = 0.64 h(- 1) Mpc, virial mass M-vir = 1.90 x 10(13) h(-1) M., total group R-band lumi nosity L-tot = 1.30 x 10(11) h(-2) L., and R-band mass-to-light ratio M/L = 171 h M./L.; the median number of observed members in a group is three.