Across

1      They want everything, according to Spooner, with qualifications.  (7)

5      Irrevocable container dent.  (7)

10    He and she, perhaps, make the element.  (4)

11    RN=CR₂ haze on time constraint.  (10)

12    Examining novel Ti/Al/Na clay.  (10)

13    Holding over time no doubt completed.  (4)

14    Means atmosphere.  (6)

16    Crazy modern 3 Down loses ore by chance.  (8)

18    Broken lace strap without a reference to lines.  (8)

21    Bully! Information for O.  (6)

23    A list from which one chooses, finally, sodium chloride solution with uranium. (4)

24    Scientist chair deems out of order.  (10)

26    It forms charged species so not an I₃ complex.  (10)

27    Cast about for subjects for Schrödinger’s paradox.  (4)

28    Any calcium telluride can be used to make (OCN)^–.  (7)

29    CH₃CONHC₆H₅, for example, is ideal in solution.  (7)

Down

2      Improve four elements.  (7)

3      August is grand.  (5)

4      More tales about stretchy polymer.  (9)

6      Perfect iodine transaction.  (5)

7      Hid dry compound adding, finally, to flux density with two –OH groups.  (9)

8      It’s C₉H₁₈O, without giving too much attention to detail.  (7)

9      Agree to study dog.  (6)

15    Addition → 5376711487.  (9)

17    Plant compound away along Nine.  (9)

19    Phony combination with 54 yields C₆H₅O–.  (7)

20    CH₃CH(OH)CO₂H as an acid sensed to be missing approval.  (6)

22    Crestfallen, lost start, thrown out.  (7)

24    A break away.  (5)

25    Transcend very big hearing.  (5)