  A library of 211 echelle spectra taken with ELODIE at the Observatoire de
Haute-Provence is presented. It provides a set of spectroscopic standards
covering the full range of gravities and metallicities in the effective
temperature interval [4000 K, 6300 K]. The spectra are straightened, wavelength
calibrated, cleaned of cosmic ray hits, bad pixels and telluric lines. They
cover the spectral range [440 nm, 680 nm] with an instrumental resolution of
42000. For each star, basic data were compiled from the Hipparcos catalogue and
the Hipparcos Input Catalogue. Radial velocities with a precision better than
100 m/s are given. Atmospheric parameters (Teff, log g, [Fe/H]) from the
literature are discussed. Because of scattered determinations in the
bibliography, even for the most well-known stars, these parameters were
adjusted by an iterative process which takes account of common or different
spectral features between the standards, using our homogeneous set of spectra.
Revised values of (Teff, log g, [Fe/H]) are proposed. They are still consistent
with the literature, and also lead to the self-consistency of the library, in
the sense that similar spectra have similar atmospheric parameters. This
adjustment was performed by using step by step a method based on the least
square comparison of carefully prepared spectra, which was originally developed
for the on-line estimation of the atmospheric parameters of faint field stars
(companion paper in the main journal). The spectra and corresponding data will
only be available in electronic form at the CDS (ftp cdsarc.u-strasbg.fr or
http://cdsweb.u-strasbg.fr/Abstract.html).
