JiscMail Logo
Email discussion lists for the UK Education and Research communities

Help for CCP4BB Archives


CCP4BB Archives

CCP4BB Archives


CCP4BB@JISCMAIL.AC.UK


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

CCP4BB Home

CCP4BB Home

CCP4BB  May 2012

CCP4BB May 2012

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: P321 space group reindex problem

From:

Vellieux Frederic <[log in to unmask]>

Reply-To:

Vellieux Frederic <[log in to unmask]>

Date:

Wed, 30 May 2012 13:13:24 +0200

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (52 lines)

Hi Ian,

You're right the information is there... but not where I was expecting 
it (on the page corresponding to an individual space group). It had 
never occurred to me that it could be somewhere else.

So thanks, and regards to Jasmine.

Fred.

Ian Tickle wrote:
> Hello Fred
>
> On 30 May 2012 07:55, Vellieux Frederic <[log in to unmask]> wrote:
>   
>> Hi there,
>>     
>
>   
>> But: trigonal (and hexagonal) space groups "are" (usually?) polar. The cell
>> axis "c"  can go "up" or can go "down", and in order to get a consistent
>> indexing you need to check both indexing systems when you scale additional
>> data to your native (the indexing chosen by your first crystals defines the
>> "standard" indexing - I must say that I haven't checked in the drawings of
>> the international tables if having c going up or going down leads to a
>> difference in that particular space group, P321, I'd need to draw both
>> possibilities and check but I'm sorry I do not have the time right now - in
>> fact it's too bad that the International Tables do not indicate "Polar" or
>> "Non-polar").
>>     
>
> It does, at least my edition (Vol. A: 5th ed., 2002, Table 10.2.1.2,
> p.806) does - ITC has everything you need to know about space groups
> (and a lot more besides)!
>
> See also this table that I made where all polar & non-polar SGs are
> listed individually:
>
> http://www.ccp4.ac.uk/dist/html/alternate_origins.html
>
> Counting only the non-enantiomorphic ones, PG3 (4 SGs) and PG6 (6 SGs)
> are polar, whereas PG321 (3 SGs), PG312 (3 SGs), PG32 (1 SG) and PG622
> (6 SGs) are non-polar.  So in all 10 are polar and 13 are non-polar.
> A 2-fold axis perp to another axis always implies that there's no
> preferred direction along the other axis, so it's non-polar.
>
> Cheers
>
> -- Ian
>
>
>   

Top of Message | Previous Page | Permalink

JISCMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007


WWW.JISCMAIL.AC.UK

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager