CREATE TABLE table_name_67 (crystal_structure VARCHAR, no_of_cu_o_planes_in_unit_cell VARCHAR, t_c__k_ VARCHAR)
Which crystal structures has a Tc(K) of 110 and the number of Cu-O planes in the unit cell is 3?
SELECT crystal_structure FROM table_name_67 WHERE no_of_cu_o_planes_in_unit_cell = 3 AND t_c__k_ = 110