error in pair coefficient

my input file is below

#============== READ CONFIGURATION =====================
read_data ZnO(1).lmp
mass 1 65.380
mass 2 15.999
#============== POTENTIAL =============================
pair_style reax/c NULL
pair_coeff **reax/c ffield.reax.ZnOH Zn O Zn

my output error is like given below

D:\files>lmp_serial.exe -in
LAMMPS (19 Sep 2019)
OMP_NUM_THREADS environment is not set. Defaulting to 1 thread. (…/comm.cpp:93)
using 1 OpenMP thread(s) per MPI task
Reading data file …
orthogonal box = (0 0 0) to (16.8849 9.7485 15.6207)
1 by 1 by 1 MPI processor grid
reading atoms …
216 atoms
read_data CPU = 0.0150008 secs
ERROR: Incorrect args for pair coefficients (…/pair_reaxc.cpp:306)

Last command: pair_coeff **reax/c ffield.reax.ZnOH Zn O Zn

kindly help me out in this regard

you should be able to resolve this yourself by carefully studying the documentation. this issue is a rather trivial one. you might also find similar questions (and corresponding answers) in the mailing list archives.

if you keep posting to the mailing list for every error that you encounter without showing that you did any serious effort in resolving it, you will soon find, that your posts will be ignored. and that would possibly include legitimate questions about real problems that cannot be easily solved without outside help.

you need to keep in mind, that people responding here are volunteering their time and thus you should respect that by trying harder to solve simple problems yourself.