  We study the coherence times and perform manipulations on the lowest-energy
states of trivalent cerium ion in calcium tungstate crystal. We find the phase
memory time reaching 14.2 ${\mu}$s and the time of coherent manipulations
reaching 0.3 ${\mu}$s in the low-temperature limit, the latter can potentially
be elongated by using the rotation angle and off-resonance error correction
schemes.
