the same as the 1 in P1 ;-)
seriously, if you look at space group names:
143 P3
144 P31
145 P32
149 P312
151 P3112
153 P3212
150 P321
152 P3121
154 P3221
the 1s in 149 to 154 are necessary to differentiate them all.
On 18 Feb 2015, at 04:51, Keller, Jacob wrote:
Dear
] On Behalf Of Keller,
Jacob
Sent: 18 February 2015 16:42
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] P3212--1's in Space Group Names?
Well, I meant no harm to the poor 1 by calling it a placeholder, but that in
the case of P3212, the 1 is simply to tell you that there is no rotation about
Sent: Wednesday, February 18, 2015 11:05 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] P3212--1's in Space Group Names?
Hmm, placeholder for me does not seem to emphasize enough the role that this
number plays in the space group names. My understanding (but I fail to remember
where I read
Laurent Maveyraud laurent.maveyr...@ipbs.fr writes:
this is explained in details in table 2.2.4.1 of vol A of
International Tables of Crystallography (p 18 in my edition).
For trigonal/hexagonal, the primary direction is along c, along the
3-fold (6-fold axis). It's the same in tetragonal
: [ccp4bb] P3212--1's in Space Group Names?
Well, I meant no harm to the poor 1 by calling it a placeholder, but that in the case of
P3212, the 1 is simply to tell you that there is no rotation about the second axis but is
instead about the third. Saying okay, nothing here amounts to being a
place
: [ccp4bb] P3212--1's in Space Group Names?
Hi Jacob
If you look at SGs P312 and P321in ITC-A you'll see that they are quite
different in terms of the arrangement of the a.u.s relative to the symmetry
axes. So essentially the 1's are there to distinguish these. The extra 1 or 2
after the 3
Hmm, placeholder for me does not seem to emphasize enough the role that this
number plays in the space group names. My understanding (but I fail to remember
where I read this ...) is that the first number is the order of the rotation
(i.e. 6,4,3,2 or 1) of the unique unit cell axis (often the
mjvanra...@cnb.csic.esmailto:mjvanra...@cnb.csic.es
Reply-To: Mark van Raaij mjvanra...@cnb.csic.esmailto:mjvanra...@cnb.csic.es
Date: Wednesday, February 18, 2015 4:10 AM
To: CCP4 bulletin board CCP4BB@JISCMAIL.AC.UKmailto:CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] P3212--1's in Space Group Names
Hi,
this is explained in details in table 2.2.4.1 of vol A of International
Tables of Crystallography (p 18 in my edition).
For trigonal/hexagonal, the primary direction is along c, along the
3-fold (6-fold axis). It's the same in tetragonal (obviously for the
4-fold axis !)..
The
, February 18, 2015 11:05 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] P3212--1's in Space Group Names?
Hmm, placeholder for me does not seem to emphasize enough the role that this
number plays in the space group names. My understanding (but I fail to remember
where I read
Dear Crystallographers,
I don't understand what the 1's are doing in space group names like P3212 or
P3112--can someone fill me in? Not easy to google this one.
JPK
***
Jacob Pearson Keller, PhD
Looger Lab/HHMI Janelia Research Campus
19700 Helix Dr,
Hi Jacob
If you look at SGs P312 and P321in ITC-A you'll see that they are quite
different in terms of the arrangement of the a.u.s relative to the symmetry
axes. So essentially the 1's are there to distinguish these. The extra 1
or 2 after the 3 of course signifies a screw axis. Note that for
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