Re: [sdpd] hydrogen bonds distances

[Leonid Solovyov <l_solovyov...@yahoo.com>]

> The results I have found show that the hydrogen bond distance 
>(say O--O distance) ranges from 2.5A to 2.7A along the family for the 
> best fit between experimental and powder patterns. Single crystal 
> results in related compounds show that this distance is around 2.6A.
>
> Does anybody have any opinion about if this variation in the hydrogen
> bond length is significant for structures solve with powder samples?

I would, first, check whether the bond variations are reproducible.
The simplest way is to prepare another sample of the same compound,
recollect the data, do the refinement with this new dataset, and
compare the results. Usually, the sample preparation is the most
critical point for a successful and precise refinement. However,
systematic errors originating from data collection and/or software may
also influence the results. My experience shows that laboratory XRD
data allow to control O-O distances within at least 0.02 A.

Best regards,
Leonid



		
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