We report Keck/ESI and VLT/UVES observations of three super-damped Lyman- \alpha quasar absorbers with H I column densities log N _ { HI } \geq 21.7 at redshifts 2 \lesssim z \lesssim 2.5 .
All three absorbers show similar metallicities ( \sim -1.3 to -1.5 dex ) , and dust depletion of Fe , Ni , and Mn .
Two of the absorbers show supersolar [ S/Zn ] and [ Si/Zn ] .
We combine our results with those for other DLAs to examine trends between N _ { HI } , metallicity , dust depletion .
A larger fraction of the super-DLAs lie close to or above the line [ X/H ] =20.59 - log N _ { HI } in the metallicity vs . N _ { HI } plot , compared to the less gas-rich DLAs , suggesting that super-DLAs are more likely to be rich in molecules .
Unfortunately , our data for Q0230-0334 and Q0743+1421 do not cover H _ { 2 } absorption lines .
For Q1418+0718 , some H _ { 2 } lines are covered , but not detected .
CO is not detected in any of our absorbers .
For DLAs with log N _ { HI } < 21.7 , we confirm strong correlation between metallicity and Fe depletion , and find a correlation between metallicity and Si depletion .
For super-DLAs , these correlations are weaker or absent .
The absorbers toward Q0230-0334 and Q1418+0718 show potential detections of weak Ly- \alpha emission , implying star formation rates of \sim 1.6 and \sim 0.7 M _ { \odot } yr ^ { -1 } , respectively ( ignoring dust extinction ) .
Upper limits on the electron densities from C II ^ { * } /C II or Si II ^ { * } /Si II are low , but are higher than the median values in less gas-rich DLAs .
Finally , systems with log N _ { HI } > 21.7 may have somewhat narrower velocity dispersions \Delta v _ { 90 } than the less gas-rich DLAs , and may arise in cooler and/or less turbulent gas .