Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 1

SDPDRR-II (Structure Determination by Powder Diffractometry Round Robin - 2 )

WWW: http://www.cristal.org/sdpdrr2/ Started: Monday 9th September Part 1 (powder indexing):

Start: Monday 9th September Finish: Sunday 13th October

8 samples 1 - 3 : Powder indexing and structure solution 4 - 8 : Powder Indexing only

> 100 downloads of the data (samples 1 to 3)

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 2

SDPDRR-II - Indexing Results WWW: http://sdpd.univ-lemans.fr/sdpdrr2/results/ 6 returns/100 downloads = 6% return rate

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 3

SDPDRR-II - Sample 1 WWW: http://sdpd.univ-lemans.fr/sdpdrr2/results/ Organisers: 10.323 7.395 8.535 90 91.29 90

Reduced cell: 7.395 8.535 10.323 91.29 90.00 90.00

P1: 10.318 7.393 8.527 90 91.3 90 P2: 10.321 7.392 13.236 90 139.90 90 P3: 10.322 14.787 8.529 90 91.35 90

Reduced cell: 8.529 10.322 14.787 90.00 90.00 91.30

P4: No solution P5: 8.523 10.327 7.397 90 90 91.34 P6: 8.525 7.394 13.230 90 128.748 90

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 4

SDPDRR-II - Sample 2 WWW: http://sdpd.univ-lemans.fr/sdpdrr2/results/ Organisers: 11.239 8.194 19.943 90 106.727 90

Reduced cell: 8.194 11.239 19.875 106.06 90.00 90.00 P1: 19.880 8.195 11.242 90 106.06 90 P2: 11.242 8.195 19.948 90 106.72 90 P3: 19.878 8.193 11.240 90 106.06 90 P4: 19.880 8.194 11.243 90 106.06 90 P5: 11.244 19.882 8.196 90 90 106.06 P6: 11.243 8.195 19.949 90 106.72 90

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 5

SDPDRR-II - Sample 3 WWW: http://sdpd.univ-lemans.fr/sdpdrr2/results/ Organisers: 18.881 18.881 18.881 90 90 90 (vol

6734Å3) P1: 13.349 13.349 9.439 90 90 90 (Tet -

1638Å3) P2: 18.878 18.878 18.878 90 90 90 P3: 13.354 13.354 9.442 90 90 90 (Tet -

1638Å3) P4: No Solution P5: 18.878 18.878 18.878 90 90 90 P6: 18.88 18.88 18.88 90 90 90

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 6

SDPDRR-II - Sample 3 Tetragonal or Cubic?

2 participants (1 and 3) obtained the same tetragonal cell instead of the correct cubic. Possibly due to default volume restrictions in the programs

used(?)

What happens if you run LePage (via Chekcell) followed by a “parsimony of extra reflections” check on the tetragonal solution

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 7

SDPDRR-II - Sample 3: Tetragonal: 1 peak unmatched - 46 hkl’s (P42MC et al) to match 25 reflections

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 8

SDPDRR-II - Sample 3: Tetragonal: Running LePage shows a cubic cell (18.885Å)

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 9

SDPDRR-II - Sample 3: Visual inspection of cubic cell implies “bad”peak could still be an impurity

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 10

SDPDRR-II - Sample 3: Cubic: 37 hkl’s to match 25 reflections (I23 et al) (vs 46 hkl’s in tetragonal)

Lachlan M. D. Cranswick (l.m.d.cranswick@dl.ac.uk) http://www.ccp14.ac.ukSlide 11

SDPDRR-II - Samples 4 to 8 WWW: http://sdpd.univ-lemans.fr/sdpdrr2/results/ Only one response - using the EFLECH/Index software of

Joerg Bergmann (http://www.bgmn.de/related.html)

S4: none suggested S5: 6.011 16.937 18.229 90 90 92.19 S6: none suggested S7: 4.417 11.479 17.126 77.87 85.09 82.67 S8: 3.796 9.368 28.915 90 90 90

Summary: Powder indexing is not easy and not routine!