It probably is I2 (== C2) so it would be better to re-integrate in C2 in Mosflm, as the true beta angle may not be precisely 90deg
The CCs and R-factors are not very good, so it is worth looking at the scores for the individual 2-fold axes output by Pointless, to check that one of the axes really is much better than the other two, ie that it is I2/C2 rather than I222
If there is real doubt, it may be better to solve the structure in both space groups, and decide later which fits the data better
Phil
On 6 Aug 2011, at 00:15, WENHE ZHONG wrote:
> Hi All,
>
> Recently I did some soaking experiments for crystals. Most of them did not change their space group (I222). But one of them seems to be a little bit different (I222 ---> I121).
> The following is the pointless data: (the data was processed by Mosflm under space group I222)
>
> Laue Group Lklhd NetZc Zc+ Zc- CC CC- Rmeas R- Delta ReindexOperator
>
> > 1 I 1 2/m 1 ** 0.687 2.55 8.25 5.71 0.83 0.57 0.32 0.52 0.0 [-h,-k,l]
> > 2 P -1 0.171 2.02 8.54 6.52 0.85 0.65 0.32 0.45 0.0 [-h,-k,1/2h+1/2k+1/2l]
> - 3 I m m m 0.050 6.98 6.98 0.00 0.70 0.00 0.42 0.00 0.0 [h,k,l]
> 4 I 1 2/m 1 0.050 0.22 7.09 6.87 0.71 0.69 0.42 0.42 0.0 [k,-h,l]
> 5 I 1 2/m 1 0.043 0.06 7.05 6.99 0.70 0.70 0.42 0.42 0.0 [h,-l,k]
>
> Best Solution: space group I 1 2 1
>
> Reindex operator: [-h,-k,l]
> Laue group probability: 0.687
> Systematic absence probability: 1.000
> Total probability: 0.687
> Space group confidence: 0.595
> Laue group confidence 0.595
>
> Unit cell: 104.1 108.6 264.8 90 90 90
>
> 54.32 to 3.41 - Resolution range used for Laue group search
>
> 54.32 to 2.25 - Resolution range in file, used for systematic absence check
>
> Number of batches in file: 400
>
> The data do not appear to be twinned, from the L-test
> :
>
> WARNING:
> The chosen output crystal system is different from that used for integration of the input file(s).
> You should rerun the integration in the chosen crystal system because the cell constraints differ.
>
> The input crystal system is body-centred orthorhombic
> (Cell: 104.1 108.6 264.8 90 90 90)
> The crystal system chosen for output is body-centred monoclinic
> (Cell: 104.1 108.6 264.8 90 90 90)
>
> I couldn't see the difference between I222 and I121. May I ask do I need to go back to the Mosflm process step and choose other space group for the processing? Thank you.
>
> King regards,
> Wenhe
>
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