patryk_wroc
Dołączył(a): 12 lip 2006, o 17:08 Posty: 32 Lokalizacja: Żory
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Krystalografia - baza zwiazków nieorganicznych ...Help me
Witam
chciałem się dowiedziec czy ktoś potrafi rozwiazać nastepujący problem
W bazie zwiazkow niorganicznych mając za zadanie znależć strukture zwiazku MgCl2 wyskakuje nam osiem pozycji ( 8 Hitów ) które umieszczam ponizej ... Potrzebuje wybrać jeden hit na podstawie ktorgo bede mogl narysować strukture sieci tego zwiazku ... pytanie moje brzmi ktory hit jest najleszy ? dlaczego wlasnie ten ? na jakiej podstawie wybieramy go a nie inny? czym róznią sie poszczególne hity ? mam kilka argumentów ale profesorek chce jeszcze ( trzeba go przekonać ) ... wiec jezeli mozecie mi pomoc to bardzo prosze o pomoc ...
*data for ICSD #17063
Coll Code 17063
Rec Date 1982/12/31
Chem Name Magnesium Dichloride - Beta
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
D(calc) 2.32
Title A new layer structure of Mg Cl2 with hexagonal close packing of the
chlorine atoms
Author(s) Bassi, I.W.;Polato, F.;Calcaterra, M.;Bart, J.C.J.
Reference Zeitschrift fuer Kristallographie (149,1979-)
(1982), 159, 297-302
Unit Cell 3.641(3) 3.641(3) 5.927(6) 90. 90. 120.
Vol 68.05
Z 1
Space Group P -3 m 1
SG Number 164
Cryst Sys trigonal/rhombohedral
Pearson hP3
Wyckoff d a
Red Cell P 3.641 3.641 5.927 90 90 119.999 68.047
Trans Red 1.000 0.000 0.000 / 0.000 1.000 0.000 / 0.000 0.000 1.000
Comments Structure type : CdI2(2H)
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 1 a 0 0 0 1. 0
Cl 1 -1 2 d 0.3333 0.6667 0.23 1. 0
*end for ICSD #17063
*data for ICSD #26157
Coll Code 26157
Rec Date 1986/10/09
Mod Date 2006/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
Min Name Chloromagnesite
D(calc) 2.41
Title An interpretation of the structures of alkaline earth chlorides in
terms of interionic forces
Author(s) Busing, W.R.
Reference Transactions of the American Crystallographic Association
(1970), 6, 57-72
Unit Cell 3.595 3.595 17.59 90. 90. 120.
Vol 196.88
Z 3
Space Group R -3 m H
SG Number 166
Cryst Sys trigonal/rhombohedral
Pearson hR3
Wyckoff c a
Red Cell RH 3.595 3.595 6.219 73.202 73.202 60 65.626
Trans Red 1.000 0.000 0.000 / 1.000 1.000 0.000 / 0.667 0.333 0.333
Comments Compound with mineral name: Chloromagnesite
The structure has been assigned a PDF number: 37-774
Structure type : CdCl2(3R)
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 3 a 0 0 0 1. 0
Cl 1 -1 6 c 0 0 0.273 1. 0
*end for ICSD #26157
*data for ICSD #51244
Coll Code 51244
Rec Date 2002/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
D(calc) 2.17
Title Determination of structure candidates of simple crystalline A B2
systems
Author(s) Wevers, M.A.C.;Schoen, J.C.;Jansen, M.
Reference Journal of Solid State Chemistry
(1998), 136, 233-246
Unit Cell 7.475 3.987 4.89 90. 90. 90.
Vol 145.74
Z 2
Space Group P m m a
SG Number 51
Cryst Sys orthorhombic
Pearson oP6
Wyckoff f e a
Red Cell P 3.987 4.89 7.475 90 89.999 89.999 145.736
Trans Red 0.000 1.000 0.000 / 0.000 0.000 -1.000 / -1.000 0.000 0.000
Comments Structure calculated theoretically
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 2 a 0 0 0 1. 0
Cl 1 -1 2 f 0.25 0.5 0.447 1. 0
Cl 2 -1 2 e 0.25 0 0.245 1. 0
*end for ICSD #51244
*data for ICSD #51245
Coll Code 51245
Rec Date 2002/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
D(calc) 2.29
Title Determination of structure candidates of simple crystalline A B2
systems
Author(s) Wevers, M.A.C.;Schoen, J.C.;Jansen, M.
Reference Journal of Solid State Chemistry
(1998), 136, 233-246
Unit Cell 4.06 4.06 4.188 90. 90. 90.
Vol 69.03
Z 1
Space Group P -4 m 2
SG Number 115
Cryst Sys tetragonal
Pearson tP3
Wyckoff g b
Red Cell P 4.06 4.06 4.188 90 90 90 69.033
Trans Red 1.000 0.000 0.000 / 0.000 1.000 0.000 / 0.000 0.000 1.000
Comments Structure calculated theoretically
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 1 b 0.5 0.5 0 1. 0
Cl 1 -1 2 g 0 0.5 0.228 1. 0
*end for ICSD #51245
*data for ICSD #51246
Coll Code 51246
Rec Date 2002/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
D(calc) 2.38
Title Determination of structure candidates of simple crystalline A B2
systems
Author(s) Wevers, M.A.C.;Schoen, J.C.;Jansen, M.
Reference Journal of Solid State Chemistry
(1998), 136, 233-246
Unit Cell 7.317 6.006 6.038 90. 90. 90.
Vol 265.35
Z 4
Space Group A m a 2
SG Number 40
Cryst Sys orthorhombic
Pearson oS12
Wyckoff b2 a
Red Cell A 4.258 4.258 7.317 90 89.999 90.304 132.673
Trans Red 0.000 0.500 -0.500 / 0.000 0.500 0.500 / 1.000 0.000 0.000
Comments Structure calculated theoretically
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 4 b 0.25 0.993 0.949 1. 0
Cl 1 -1 4 b 0.25 0.165 0.426 1. 0
Cl 2 -1 4 a 0 0 0.277 1. 0
*end for ICSD #51246
*data for ICSD #51247
Coll Code 51247
Rec Date 2002/04/01
Mod Date 2004/10/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
D(calc) 1.13
Title Determination of structure candidates of simple crystalline A B2
systems
Author(s) Wevers, M.A.C.;Schoen, J.C.;Jansen, M.
Reference Journal of Solid State Chemistry
(1998), 136, 233-246
Unit Cell 6.695 7.663 6.084 103.53 95.05 67.51
Vol 280.39
Z 2
Space Group P -1
SG Number 2
Cryst Sys triclinic
Pearson aP6
Wyckoff i2 g f
Red Cell P 6.084 6.695 7.663 67.51 76.469 84.949 280.389
Trans Red 0.000 0.000 1.000 / -1.000 0.000 0.000 / 0.000 -1.000 0.000
Comments Cl3-position from author, structure not quantummechanical
optimized
Structure calculated theoretically
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 2 i 0.852 0.863 0.476 1. 0
Cl 1 -1 1 g 0 0.5 0.5 1. 0
Cl 2 -1 1 f 0.5 0 0.5 1. 0
Cl 3 -1 2 i 0.013 0.076 0.858 1. 0
*end for ICSD #51247
*data for ICSD #56147
Coll Code 56147
Rec Date 2003/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
Min Name Chloromagnesite
D(calc) 2.23
Title Crystal structures of the chlorides of divalent elements
Author(s) Pauling, L.
Reference Proceedings of the National Academy of Sciences, U.S.A.
(1929), 15, 709-712
Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, Rendiconti, Serie 7 (1, 1925-1945)
(1927), 6, 56-59
Unit Cell 3.73 3.73 17.64 90. 90. 120.
Vol 212.54
Z 3
Space Group R -3 m H
SG Number 166
Cryst Sys trigonal/rhombohedral
Pearson hR3
Wyckoff c a
Red Cell RH 3.73 3.73 6.261 72.672 72.672 60 70.848
Trans Red 1.000 0.000 0.000 / 1.000 1.000 0.000 / 0.667 0.333 0.333
Comments Cell from 2nd reference: 3.60, 17.64
Compound with mineral name: Chloromagnesite
The structure has been assigned a PDF number: 37-774
Structure type : CdCl2(3R)
X-ray diffraction (powder)
No R value given in the paper.
At least one temperature factor missing in the paper.
Atom # OX SITE x y z SOF H
Mg 1 +2 3 a 0 0 0 1. 0
Cl 1 -1 6 c 0 0 0.25 1. 0
*end for ICSD #56147
*data for ICSD #86439
Coll Code 86439
Rec Date 1999/11/30
Mod Date 2003/04/01
Chem Name Magnesium Chloride
Structured Mg Cl2
Sum Cl2 Mg1
ANX AX2
Min Name Chloromagnesite
D(calc) 2.34
Title The structures and crystal chemistry of magnesium chloride and
cadmium chloride
Author(s) Partin, D.E.;O'Keefe, M.
Reference Journal of Solid State Chemistry
(1991), 95, 176-183
Unit Cell 3.6363(1) 3.6363(1) 17.66629(50) 90. 90. 120.
Vol 202.3
Z 3
Space Group R -3 m H
SG Number 166
Cryst Sys trigonal/rhombohedral
Pearson hR3
Wyckoff c a
R Value 0.1
Red Cell RH 3.636 3.636 6.251 73.092 73.092 60 67.433
Trans Red 1.000 0.000 0.000 / 1.000 1.000 0.000 / 0.667 0.333 0.333
Comments Compound with mineral name: Chloromagnesite
The structure has been assigned a PDF number: 37-774
Rietveld profile refinement applied
Structure type : CdCl2(3R)
X-ray diffraction (powder)
Atom # OX SITE x y z SOF H
Mg 1 +2 3 a 0 0 0 1. 0
Cl 1 -1 6 c 0 0 0.25784(8) 1. 0
Lbl Type U11 U22 U33 U12 U13 U23
Mg1 Mg2+ 0.025(2) 0.025(2) 0.027(2) 0.012(2) 0 0
Cl1 Cl1- 0.045(2) 0.045(2) 0.003(1) 0.0220(9) 0 0
*end for ICSD #86439
z góry dziękuję za pomoc
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wojtex
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Dołączył(a): 28 lis 2006, o 14:14 Posty: 416
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Tak jest. Tylko w ostatnim przykładzie jest podany czynnik dokładności R. Wynosi on 0.1. Nie jestem pewien, czy to jest 0.1%, co by oznaczało genialną dokładność, czy raczej 10%, co by oznaczało paskudną dokładność. W każdym razie podanie R jest uważane za bardziej wiarygodne niż niepodanie tego czynnika.
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