CREATE TABLE "critical_temperature_t_c_crystal_structu" (
  "formula" text,
  "notation" text,
  "t_c_k" real,
  "no_of_cu_o_planes_in_unit_cell" real,
  "crystal_structure" text
);

Question: What is the notion when the crystal structure is tetragonal and the formula is bi 2 sr 2 cacu 2 o 8
SQL: SELECT "notation" FROM "critical_temperature_t_c_crystal_structu" WHERE "crystal_structure"='Tetragonal' AND "formula"='Bi 2 Sr 2 CaCu 2 O 8';

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

Question: What is the crystal structure for the formula yba 2 cu 3 o 7?
SQL: SELECT "crystal_structure" FROM "critical_temperature_t_c_crystal_structu" WHERE "formula"='YBa 2 Cu 3 O 7';

Question: What is the number for t c (k) when the notation is tl-2212?
SQL: SELECT COUNT("t_c_k") FROM "critical_temperature_t_c_crystal_structu" WHERE "notation"='Tl-2212';