Table schema:
CREATE TABLE table_101336_1 (no_of_cu_o_planes_in_unit_cell VARCHAR, formula VARCHAR)

Question: How many times is the formula tl 2 ba 2 cuo 6?
SQL: SELECT no_of_cu_o_planes_in_unit_cell FROM table_101336_1 WHERE formula = "Tl 2 Ba 2 CuO 6"