Thread View: sci.techniques.xtallography
3 messages
3 total messages
Started by Uncle Al
Thu, 15 Nov 2001 20:19
Crystal Unit Cell Question
Author: Uncle Al
Date: Thu, 15 Nov 2001 20:19
Date: Thu, 15 Nov 2001 20:19
45 lines
2482 bytes
2482 bytes
Uncle Al asks a probably silly and very obvious question about some crystal data... REFERENCE STRUCTURE = 20626 A,B,C = 5.482 5.482 5.173 ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =173 P63 3 0 CODEN= 46025 SYMOPS= 389 40 RFAC= 2.1 ERRFLAG=0 (C-C)ESD=0 1 Li1 0.00000 0.00000 0.07830 2 O1 0.24750 0.34220 -0.16200 3 I1 0.33333 0.66667 0.00000 Lithium iodate, LiIO(3), has two formula units in its unit cell: 2 lithiums 2 iodines 6 oxygens ----- Where are the rest of the atoms? ----- REFERENCE STRUCTURE = 47670 A,B,C = 4.913 4.913 5.405 ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =154 P3221 2 0 CODEN= 83849 SYMOPS= 398 40 RFAC= 2.4 ERRFLAG=0 (C-C)ESD=0 1 Si1 0.46980 0.00000 0.16667 2 O1 0.41380 0.26510 0.28710 Alpha-quartz, SiO(2), has three formula units in its unit cell, 3 silicons 6 oxygens ----- Where are the rest of the atoms? ----- Remember, I am an organic chemist. We do our best work unclogging drains and making soybean waste taste like hamburger. The Devil lies in the details, so make it simple for a simple person. Post 'em if you've got 'em! Thank you. -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net!
Re: Crystal Unit Cell Question
Author: Bev Vincent
Date: Thu, 15 Nov 2001 20:35
Date: Thu, 15 Nov 2001 20:35
57 lines
3222 bytes
3222 bytes
"Uncle Al" <UncleAl0@hate.spam.net> wrote in message news:3BF42339.6F5822E@hate.spam.net... > Uncle Al asks a probably silly and very obvious question about some > crystal data... > > REFERENCE STRUCTURE = 20626 A,B,C = 5.482 5.482 5.173 > ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =173 P63 > 3 0 CODEN= 46025 SYMOPS= 389 > 40 RFAC= 2.1 ERRFLAG=0 (C-C)ESD=0 > 1 Li1 0.00000 0.00000 0.07830 > 2 O1 0.24750 0.34220 -0.16200 > 3 I1 0.33333 0.66667 0.00000 > > Lithium iodate, LiIO(3), has two formula units in its unit cell: > > 2 lithiums > 2 iodines > 6 oxygens > > ----- Where are the rest of the atoms? ----- Space Group P63 (#173) has the following symmetry operators: 1) +X, +Y, +Z 2) -Y, +X-Y, +Z 3) -X+Y, -X, +Z 4) -X, -Y, 1/2+Z 5) +Y, -X+Y, 1/2+Z 6) +X-Y, +X, 1/2+Z Take the above coordinates for Li1, I1 and O1 and apply these operations. If an atom is on a special position, some of these operations will return the same coordinates (e.g. 0, 0, .0783 produces the same coordinates for operators 1-3 and the second position -- 0, 0, 0.5783 -- for operators 4-6). > REFERENCE STRUCTURE = 47670 A,B,C = 4.913 4.913 5.405 > ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =154 P3221 > 2 0 CODEN= 83849 SYMOPS= 398 > 40 RFAC= 2.4 ERRFLAG=0 (C-C)ESD=0 > 1 Si1 0.46980 0.00000 0.16667 > 2 O1 0.41380 0.26510 0.28710 > > Alpha-quartz, SiO(2), has three formula units in its unit cell, > > 3 silicons > 6 oxygens > > ----- Where are the rest of the atoms? ----- P3221 (#154) has these operators: 1) +X, +Y, +Z 2) -Y, +X-Y, 2/3+Z 3) -X+Y, -X, 1/3+Z 4) +Y, +X, -Z 5) -X, -X+Y, 2/3-Z 6) +X-Y, -Y, 1/3-Z Same game as before. Bev Vincent Rigaku/MSC http://www.RigakuMSC.com
Re: Crystal Unit Cell Question
Author: Uncle Al
Date: Thu, 15 Nov 2001 22:38
Date: Thu, 15 Nov 2001 22:38
74 lines
3733 bytes
3733 bytes
Bev Vincent wrote: > > "Uncle Al" <UncleAl0@hate.spam.net> wrote in message > news:3BF42339.6F5822E@hate.spam.net... > > Uncle Al asks a probably silly and very obvious question about some > > crystal data... > > > > REFERENCE STRUCTURE = 20626 A,B,C = 5.482 5.482 5.173 > > ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =173 P63 > > 3 0 CODEN= 46025 SYMOPS= 389 > > 40 RFAC= 2.1 ERRFLAG=0 (C-C)ESD=0 > > 1 Li1 0.00000 0.00000 0.07830 > > 2 O1 0.24750 0.34220 -0.16200 > > 3 I1 0.33333 0.66667 0.00000 > > > > Lithium iodate, LiIO(3), has two formula units in its unit cell: > > > > 2 lithiums > > 2 iodines > > 6 oxygens > > > > ----- Where are the rest of the atoms? ----- > > Space Group P63 (#173) has the following symmetry operators: > > 1) +X, +Y, +Z 2) -Y, +X-Y, +Z > 3) -X+Y, -X, +Z 4) -X, -Y, 1/2+Z > 5) +Y, -X+Y, 1/2+Z 6) +X-Y, +X, 1/2+Z > > Take the above coordinates for Li1, I1 and O1 and apply these operations. If > an atom is on a special position, some of these operations will return the > same coordinates (e.g. 0, 0, .0783 produces the same coordinates for > operators 1-3 and the second position -- 0, 0, 0.5783 -- for operators 4-6). > > > REFERENCE STRUCTURE = 47670 A,B,C = 4.913 4.913 5.405 > > ALPHA,BETA,GAMMA = 90.000 90.000 120.000 SPGR =154 P3221 > > 2 0 CODEN= 83849 SYMOPS= 398 > > 40 RFAC= 2.4 ERRFLAG=0 (C-C)ESD=0 > > 1 Si1 0.46980 0.00000 0.16667 > > 2 O1 0.41380 0.26510 0.28710 > > > > Alpha-quartz, SiO(2), has three formula units in its unit cell, > > > > 3 silicons > > 6 oxygens > > > > ----- Where are the rest of the atoms? ----- > > P3221 (#154) has these operators: > > 1) +X, +Y, +Z 2) -Y, +X-Y, 2/3+Z > 3) -X+Y, -X, 1/3+Z 4) +Y, +X, -Z > 5) -X, -X+Y, 2/3-Z 6) +X-Y, -Y, 1/3-Z > > Same game as before. > > Bev Vincent > Rigaku/MSC > http://www.RigakuMSC.com I should have been a social activist. Exercise of objective competence is such a nuisance... I limbered up my HP-15C and visited http://sbl.salk.edu/~jason/Public/spacegroup.html#173 Clever folks those x-ray crystallographers. Thanx guyss! I'll withdraw my post now. -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net!
Thread Navigation
This is a paginated view of messages in the thread with full content displayed inline.
Messages are displayed in chronological order, with the original post highlighted in green.
Use pagination controls to navigate through all messages in large threads.
Back to All Threads