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Comments on list #5




CoreDEF Colleagues,

Some of my comments may be completely off of the wall as I am new to this
business.  In any case I hope they are helpful.
 
Comments - 

_exptl_crystal_density_meas_gt or lt

Is this really a measured density or is it an observation related to
density.  
Like Syd, the lt and gt made no sense to me until I had read David's
explanation.
This suggests that we need more information Presumably the scientist would
put how less than 1.0 was determined by an entry in
_exptl_crystal_density_meas_method  _exptl_crystal_density_meas_method would
benefit from additional example - perhaps 
"sample floats in water" or "sample sinks in ethanol" 
The definition should include some examples Davids comment make a good start
on the example

_exptl_crystal_appearance_colour_primary etc

>From a practical point of view, what do I do with my old database entries
that have red orange as a single entry.  
Do I have to separate them to get a good cif?  Personally I prefer yellow
green to yellowish green  

If we have lists for colors, do we want to have a similar list for
_exptl_crystal_description.  Has that entry been dealt with already?  
Would _exptl_crystal_habit be useful?

_exptl_crystal_recrystallzation_method

Will this be an enumerated list like color?  Seems like it would be useful
to have a list.  Sublimation, evaporation, cooling, serendipity,
spontaneous, vapor diffusion, gel diffusion,   .....
Then there should be a _exptl_crystal_recrystallzation_method_details
section for more information like temperature and solvents. 


I think the Syd's suggestions for the extinction are fine.

In the symmetry entries can we please keep Int_Tables  IT sounds like my
Information Technologies department.  If we can have an entry as long as
_exptl_crystal_appearance_colour_primary then we can certainly have
_space_group_Int_Tables_number.  As a novice, what happens to current
symmetry entries.  I assume they translate into the new cif and that cif
reads will know that _symmetry_equiv_pos_as_xyz is the same as
_space_group_symop_operation_xyz.  Why that name doesn't symop imply
operation.  Why are we replacing _symmetry_equiv_pos_as_xyz which seems to
be an accurate desciption of "1/2-x,1/2+y,1/2-z" for example.

Curt Haltiwanger
===============================================
R. Curtis 'Curt' Haltiwanger
Senior Application Scientist       Bruker-AXS
5465 East Cheryl Parkway         Madison WI 53711-5373

Phone:   (608)276-3073             FAX:      (608)276-3006
Mobile:   (608)347-8694   
E-mail:  CHaltiwanger@bruker-axs.com
WWW:  Bruker-AXS.com
===============================================


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