  By using a hydrothermal ion-exchange method, we have successfully grown
superconducting crystals of LiOHFeS with ${T_c}$ of about 2.8 K. Being
different from the sister sample (Li${_{1-x}}$Fe${_x}$)OHFeSe, the energy
dispersion spectrum analysis on LiOHFeS shows that the Fe/S ratio is very close
to 1:1, suggesting an almost charge neutrality and less electron doping in the
FeS planes of the system. Comparing with the non superconducting LiOHFeS
crystal, each peak of the X-ray diffraction pattern of the superconducting
crystal splits into two, and the diffraction peaks locating at lower reflection
angles are consistent with that of non-superconducting ones. The rest set of
diffraction peaks with higher reflection angles is corresponding to the
superconducting phase, suggesting that the superconducting phase may has a
shrunk c-axis lattice constant. Magnetization measurements indicate that the
magnetic shielding due to superconductivity can be quite high under a weak
magnetic field. The resistivity measurements under various magnetic fields show
that the upper critical field is quite low, which is similar to the tetragonal
FeS superconductor.
