Since there is a real possibility that it is I2 but most of the crystals are
pseudo-merohedrally twinned emulating I222, this is a case where I would
recommend keeping the I2 setting with beta close to 90 degrees rather than
converting to the more conventional C2 cell. Most modern programs (and some
older ones) should have no problems with I2.
George
On Sat, Aug 06, 2011 at 12:15:27AM +0100, 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
>
--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-3021 or -3068
Fax. +49-551-39-22582
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