The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey:
  Large-scale Structure Catalogs for Cosmological Analysis
  We present large-scale structure catalogs from the completed extended Baryon
Oscillation Spectroscopic Survey (eBOSS). Derived from Sloan Digital Sky Survey
(SDSS) -IV Data Release 16 (DR16), these catalogs provide the data samples,
corrected for observational systematics, and random positions sampling the
survey selection function. Combined, they allow large-scale clustering
measurements suitable for testing cosmological models. We describe the methods
used to create these catalogs for the eBOSS DR16 Luminous Red Galaxy (LRG) and
Quasar samples. The quasar catalog contains 343,708 redshifts with $0.8 < z <
2.2$ over 4,808\,deg$^2$. We combine 174,816 eBOSS LRG redshifts over
4,242\,deg$^2$ in the redshift interval $0.6 < z < 1.0$ with SDSS-III BOSS LRGs
in the same redshift range to produce a combined sample of 377,458 galaxy
redshifts distributed over 9,493\,deg$^2$. Improved algorithms for estimating
redshifts allow that 98 per cent of LRG observations result in a successful
redshift, with less than one per cent catastrophic failures ($\Delta z > 1000$
${\rm km~s}^{-1}$). For quasars, these rates are 95 and 2 per cent (with
$\Delta z > 3000$ ${\rm km~s}^{-1}$). We apply corrections for trends between
the number densities of our samples and the properties of the imaging and
spectroscopic data. For example, the quasar catalog obtains a $\chi^2$/DoF$=
776/10$ for a null test against imaging depth before corrections and a
$\chi^2$/DoF$=6/8$ after. The catalogs, combined with careful consideration of
the details of their construction found here-in, allow companion papers to
present cosmological results with negligible impact from observational
systematic uncertainties.
