Number of electron deficient molecules among the following \( \mathrm{PH_3} \), \( \mathrm{B_2H_6} \), \( \mathrm{CCl_4} \), \( \mathrm{NH_3} \), \( \mathrm{LiH} \) and \( \mathrm{BCl_3} \) is:
\( 0 \)
\( 1 \)
\( 2 \)
\( 3 \)