Periodic table (crystal structure)

Source: Wikipedia, the free encyclopedia.

For elements that are solid at standard temperature and pressure the first table gives the crystalline structure of the most thermodynamically stable form(s) in those conditions. Each element is shaded by a color representing its respective Bravais lattice, except that all orthorhombic lattices are grouped together.


Standard temperature and pressure

Crystal structure of elements in the periodic table at standard temperature and pressure[1]
1
H
 
2
He
 
3
Li
W
4
Be
Mg
5
B
β-B
6
C
g-C
7
N
 
8
O
 
9
F
 
10
Ne
 
11
Na
W
12
Mg
Mg
13
Al
Cu
14
Si
d-C
15
P
b-P
16
S
α-S
17
Cl
 
18
Ar
 
19
K
W
20
Ca
Cu
21
Sc
Mg
22
Ti
Mg
23
V
W
24
Cr
W
25
Mn
α-Mn
26
Fe
W
27
Co
Mg
28
Ni
Cu
29
Cu
Cu
30
Zn
Mg
31
Ga
α-Ga
32
Ge
d-C
33
As
α-As
34
Se
γ-Se
35
Br
 
36
Kr
 
37
Rb
W
38
Sr
Cu
39
Y
Mg
40
Zr
Mg
41
Nb
W
42
Mo
W
43
Tc
Mg
44
Ru
Mg
45
Rh
Cu
46
Pd
Cu
47
Ag
Cu
48
Cd
Mg
49
In
In
50
Sn
β-Sn
51
Sb
α-As
52
Te
γ-Se
53
I
Cl
54
Xe
 
55
Cs
W
56
Ba
W
1 asterisk 71
Lu
Mg
72
Hf
Mg
73
Ta
W
74
W
W
75
Re
Mg
76
Os
Mg
77
Ir
Cu
78
Pt
Cu
79
Au
Cu
80
Hg
 
81
Tl
Mg
82
Pb
Cu
83
Bi
α-As
84
Po
α-Po
85
At
 
86
Rn
 
87
Fr
 
88
Ra
W
2 asterisks 103
Lr
 
104
Rf
 
105
Db
 
106
Sg
 
107
Bh
 
108
Hs
 
109
Mt
 
110
Ds
 
111
Rg
 
112
Cn
 
113
Nh
 
114
Fl
 
115
Mc
 
116
Lv
 
117
Ts
 
118
Og
 

1 asterisk 57
La
α-La
58
Ce
α-La
59
Pr
α-La
60
Nd
α-La
61
Pm
α-La
62
Sm
α-Sm
63
Eu
W
64
Gd
Mg
65
Tb
Mg
66
Dy
Mg
67
Ho
Mg
68
Er
Mg
69
Tm
Mg
70
Yb
Cu
2 asterisks 89
Ac
Cu
90
Th
Cu
91
Pa
α-Pa
92
U
α-U
93
Np
α-Np
94
Pu
α-Pu
95
Am
α-La
96
Cm
α-La
97
Bk
α-La
98
Cf
α-La
99
Es
Cu
100
Fm
 
101
Md
 
102
No
 
Legend:
  Primitive monoclinic structures: α-Pu
  Orthorhombic structures: b-P, α-Ga, Cl, α-U, α-S, α-Np
  Body-centered tetragonal structures: In, β-Sn, α-Pa
  Rhombohedral structures: β-B, α-As, α-Sm
  Hexagonal structures: Mg, α-La, g-C, γ-Se
  
Primitive cubic
structures: α-Po
  
Body-centered cubic
structures: W, α-Mn
  
Face-centered cubic
structures: d-C, Cu
  Not solid at standard temperature and pressure or uncertain

Melting point and standard pressure

The second table gives the most stable structure of each element at its melting point. (H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, and Rn are gases at STP; Br and Hg are liquids at STP.) Note that helium does not have a melting point at atmospheric pressure, but it adopts a magnesium-type hexagonal close-packed structure under high pressure.

Crystal structures of elements at their melting points at atmospheric pressure
1
H
13 K
Mg
2
He
*
3
Li
453 K
W
4
Be
1560 K
W
5
B
2349 K
β-B
6
C
3800 K
g-C
7
N
63 K
β-N
8
O
54 K
γ-O
9
F
53 K
γ-O
10
Ne
24 K
Cu
11
Na
370 K
W
12
Mg
923 K
Mg
13
Al
933 K
Cu
14
Si
1687 K
d-C
15
P
883 K
b-P
16
S
368 K
α-S
17
Cl
171 K
Cl
18
Ar
83 K
Cu
19
K
336 K
W
20
Ca
1115 K
W
21
Sc
1814 K
W
22
Ti
1941 K
W
23
V
2183 K
W
24
Cr
2180 K
W
25
Mn
1519 K
W
26
Fe
1811 K
W
27
Co
1768 K
Cu
28
Ni
1728 K
Cu
29
Cu
1357 K
Cu
30
Zn
692 K
Mg
31
Ga
302 K
α-Ga
32
Ge
1211 K
d-C
33
As
1090 K
b-P
34
Se
494 K
γ-Se
35
Br
265 K
Cl
36
Kr
115 K
Cu
37
Rb
312 K
W
38
Sr
1050 K
W
39
Y
1799 K
W
40
Zr
2128 K
W
41
Nb
2750 K
W
42
Mo
2896 K
W
43
Tc
2430 K
Mg
44
Ru
2607 K
Mg
45
Rh
2237 K
Cu
46
Pd
1828 K
Cu
47
Ag
1234 K
Cu
48
Cd
594 K
Mg
49
In
429 K
In
50
Sn
505 K
β-Sn
51
Sb
903 K
α-As
52
Te
722 K
γ-Se
53
I
386 K
Cl
54
Xe
161 K
Cu
55
Cs
301 K
W
56
Ba
1000 K
W
1 asterisk 71
Lu
1925 K
Mg
72
Hf
2506 K
W
73
Ta
3290 K
W
74
W
3695 K
W
75
Re
3459 K
Mg
76
Os
3306 K
Mg
77
Ir
2719 K
Cu
78
Pt
2041 K
Cu
79
Au
1337 K
Cu
80
Hg
234 K
α-Hg
81
Tl
557 K
W
82
Pb
600 K
Cu
83
Bi
544 K
α-As
84
Po
527 K
β-Po
85
At
575 K?
?
86
Rn
202 K
?
87
Fr
281 K?
?
88
Ra
973 K
W
2 asterisks 103
Lr
1900 K?
?
104
Rf
?
105
Db
?
106
Sg
?
107
Bh
?
108
Hs
?
109
Mt
?
110
Ds
?
111
Rg
?
112
Cn
?
113
Nh
?
114
Fl
?
115
Mc
?
116
Lv
?
117
Ts
?
118
Og
?

1 asterisk 57
La
1193 K
W
58
Ce
1068 K
W
59
Pr
1208 K
W
60
Nd
1297 K
W
61
Pm
1315 K
W
62
Sm
1345 K
W
63
Eu
1099 K
W
64
Gd
1585 K
W
65
Tb
1629 K
W
66
Dy
1680 K
W
67
Ho
1734 K
Mg
68
Er
1802 K
Mg
69
Tm
1818 K
Mg
70
Yb
1097 K
W
2 asterisks 89
Ac
1323 K
Cu
90
Th
2115 K
W
91
Pa
1841 K
W
92
U
1405 K
W
93
Np
917 K
W
94
Pu
912 K
W
95
Am
1449 K
W
96
Cm
1613 K
Cu
97
Bk
1259 K
Cu
98
Cf
1173 K
Cu
99
Es
1133 K
Cu
100
Fm
1800 K?
?
101
Md
1100 K?
?
102
No
1100 K?
?
Legend:
  Orthorhombic structures: b-P, α-S, Cl, α-Ga
  Body-centered tetragonal structures: In, β-Sn
  Rhombohedral structures: β-B, α-As, α-Hg, α-Po
  Primitive Hexagonal structures: Mg, g-C, β-N, γ-Se
  
Primitive cubic
structure: γ-O
  
Body-centered cubic
structure: W
  
Face-centered cubic
structures: Cu, d-C
  unknown or uncertain

Predicted structures

Predictions are given for elements 85–87, 100–113 and 118; all but radon[2] have not been produced in bulk. Probably Cn and Fl are liquids at STP. Calculations have difficulty replicating the experimentally known bcc structures of the stable alkali metals, and the same problem affects Fr (87);[3] nonetheless, it is probably also bcc.[4] The latest predictions for Fl (114) could not distinguish between face-centred cubic and hexagonal close-packed structures, which were predicted to be close in energy.[5] No predictions are available for elements 115–117.

Predicted crystal structures of highly unstable elements
1
H
2
He
3
Li
4
Be
5
B
6
C
7
N
8
O
9
F
10
Ne
11
Na
12
Mg
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
19
K
20
Ca
21
Sc
22
Ti
23
V
24
Cr
25
Mn
26
Fe
27
Co
28
Ni
29
Cu
30
Zn
31
Ga
32
Ge
33
As
34
Se
35
Br
36
Kr
37
Rb
38
Sr
39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
50
Sn
51
Sb
52
Te
53
I
54
Xe
55
Cs
56
Ba
1 asterisk 71
Lu
72
Hf
73
Ta
74
W
75
Re
76
Os
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
85
At
[Cu][6]
86
Rn
[Cu][7]
87
Fr
[W][4]
88
Ra
2 asterisks 103
Lr
[Mg][8]
104
Rf
[Mg][8]
105
Db
[W][8]
106
Sg
[W][8]
107
Bh
[Mg][8]
108
Hs
[Mg][9]
109
Mt
[Cu][8]
110
Ds
[W][8]
111
Rg
[W][8]
112
Cn
[Mg][10]
113
Nh
[Mg][11]
114
Fl
 
115
Mc
 
116
Lv
 
117
Ts
 
118
Og
[Cu][7]

1 asterisk 57
La
58
Ce
59
Pr
60
Nd
61
Pm
62
Sm
63
Eu
64
Gd
65
Tb
66
Dy
67
Ho
68
Er
69
Tm
70
Yb
2 asterisks 89
Ac
90
Th
91
Pa
92
U
93
Np
94
Pu
95
Am
96
Cm
97
Bk
98
Cf
99
Es
100
Fm
[Cu][12]
101
Md
[Cu][12]
102
No
[Cu][12]
Legend:
[…] predicted structure
  Elements with known structure.
  
Body-centered cubic
structure: W
  
Face-centered cubic
structures: Cu
  Primitive Hexagonal structures: Mg
  unknown or uncertain

Structure types

The following is a list of structure types which appear in the tables above. Regarding the number of atoms in the unit cell, structures in the rhombohedral lattice system have a rhombohedral primitive cell and have trigonal point symmetry but are also often also described in terms of an equivalent but nonprimitive hexagonal unit cell with three times the volume and three times the number of atoms.

Prototype Strukturbericht Diagram
Lattice system
Space group Atoms per unit cell Coordination notes
α-Pu (none) Monoclinic P21/m
(No. 11)
16 slightly distorted hexagonal structure. Lattice parameters: a = 618.3 pm, b = 482.2 pm, c = 1096.3 pm, β = 101.79° [13][14]
α-Np Ac Orthorhombic Pnma
(No. 62)
8 highly distorted bcc structure. Lattice parameters: a = 666.3 pm, b = 472.3 pm, c = 488.7 pm [15][16]
α-U A20 Orthorhombic Cmcm
(No. 63)
4 Each atom has four near neighbours, 2 at 275.4 pm, 2 at 285.4 pm. The next four at distances 326.3 pm and four more at 334.2 pm.[17] Strongly distorted hcp structure.
α-Ga A11 Orthorhombic Cmce
(No. 64)
8 each Ga atom has one nearest neighbour at 244 pm, 2 at 270 pm, 2 at 273 pm, 2 at 279 pm.[18] The structure is related to that of iodine.
b-P A17 Orthorhombic Cmce
(No. 64)
8 Specifically the
black phosphorus
form of phosphorus.
Cl A14 Orthorhombic Cmce
(No. 64)
8
α-S A16 Orthorhombic Fddd
(No. 70)
16
In A6 Tetragonal I4/mmm
(No. 139)
2 Identical symmetry to the α-Pa type structure. Can be considered slightly distorted from an ideal Cu type face-centered cubic structure[18] which has .
α-Pa Aa Tetragonal I4/mmm
(No. 139)
2 Identical symmetry to the In type structure. Can be considered slightly distorted from an ideal W type body centered cubic structure which has .
β-Sn A5 Tetragonal I41/amd
(No. 141)
4 4 neighbours at 302 pm; 2 at 318 pm; 4 at 377 pm; 8 at 441 pm [18] white tin form (thermodynamical stable above 286.4 K)
β-B (none) Rhombohedral R3m
(No. 166)
105 (rh.)
315 (hex.)
Partly due to its complexity, whether this structure is the ground state of Boron has not been fully settled.
α-As A7 Rhombohedral R3m
(No. 166)
2 (rh.)
6 (hex.)
in grey metallic form, each As atom has 3 neighbours in the same sheet at 251.7pm; 3 in adjacent sheet at 312.0 pm.[18]
each Bi atom has 3 neighbours in the same sheet at 307.2 pm; 3 in adjacent sheet at 352.9 pm.[18]
each Sb atom has 3 neighbours in the same sheet at 290.8pm; 3 in adjacent sheet at 335.5 pm.[18]
puckered sheet
α-Sm (none) Rhombohedral R3m
(No. 166)
3 (rh.)
9 (hex.)
12 nearest neighbours complex hcp with 9-layer repeat: ABCBCACAB....[19]
α-Hg A10 Rhombohedral R3m
(No. 166)
1 (rh.)
3 (hex.)
6 nearest neighbours at 234 K and 1 atm (it is liquid at room temperature and thus has no crystal structure at ambient conditions!) Identical symmetry to the β-Po structure, distinguished based on details about the basis vectors of its unit cell. This structure can also be considered to be a distorted hcp lattice with the nearest neighbours in the same plane being approx 16% farther away [18]
β-Po Ai Rhombohedral R3m
(No. 166)
1 (rh.)
3 (hex.)
Identical symmetry to the α-Hg structure, distinguished based on details about the basis vectors of its unit cell.
γ-Se A8
Hexagonal
P321
(No. 154)
3
Mg A3
Hexagonal
P63/mmc
(No. 194)
2 Zn has 6 nearest neighbors in same plane: 6 in adjacent planes 14% farther away[18]
Cd has 6 nearest neighbours in the same plane- 6 in adjacent planes 15% farther away[18]
If the unit cell axial ratio is exactly the structure would be a mathematical hexagonal close packed (HCP) structure. However, in real materials there are deviations from this in some metals where the unit cell is distorted in one direction but the structure still retains the hcp space group—remarkable all the elements have a ratio of lattice parameters c/a < 1.633 (best are Mg and Co and worst Be with c/a ~ 1.568). In others like Zn and Cd the deviations from the ideal change the symmetry of the structure and these have a lattice parameter ratio c/a > 1.85.
g-C A9
Hexagonal
P63/mmc
(No. 194)
4 Specifically the graphite form of carbon.
α-La A3'
Hexagonal
P63/mmc
(No. 194)
4 The Double hexagonal close packed (DHCP) structure. Similar to the ideal hcp structure, the perfect dhcp structure should have a lattice parameter ratio of In the real dhcp structures of 5 lanthanides (including β-Ce) variates between 1.596 (Pm) and 1.6128 (Nd). For the four known actinides dhcp lattices the corresponding number vary between 1.620 (Bk) and 1.625 (Cf).[20]
β-N (none)
Hexagonal
P63/mmc
(No. 194)
4
α-Po Ah Cubic Pm3m
(No. 221)
1 6 nearest neighbours simple cubic lattice. The atoms in the unit cell are at the corner of a cube.
γ-O (none) Cubic Pm3n
(No. 223)
16 Closely related to the β-W structure, except with a diatomic oxygen molecule in place of each tungsten atom. The molecules can rotate in place, but the direction of rotation for some of the molecules is restricted.
α-Mn A12 Cubic I43m
(No. 217)
58 Unit cell contains Mn atoms in 4 different environments.[18] Distorted bcc
W A2 Cubic Im3m
(No. 229)
2 The Body centered cubic structure (BCC). It is not a close packed structure. In this each metal atom is at the centre of a cube with 8 nearest neighbors, however the 6 atoms at the centres of the adjacent cubes are only approximately 15% further away so the coordination number can therefore be considered to be 14 when these are on one 4 fold axe structure becomes face-centred cubic (cubic close packed).
Cu A1 Cubic Fm3m
(No. 225)
4 The face-centered cubic (cubic close packed) structure. More content relating to number of planes within structure and implications for glide/slide e.g. ductility.
d-C A4 Cubic Fd3m
(No. 227)
8 The diamond cubic (DC) structure. Specifically the diamond form of Carbon.

Close packed metal structures

The observed crystal structures of many metals can be described as a nearly mathematical close-packing of equal spheres. A simple model for both of these is to assume that the metal atoms are spherical and are packed together as closely as possible. In closest packing, every atom has 12 equidistant nearest neighbours, and therefore a coordination number of 12. If the close packed structures are considered as being built of layers of spheres, then the difference between hexagonal close packing and face-centred cubic is how each layer is positioned relative to others. The following types can be viewed as a regular buildup of close-packed layers:

  • Mg type (hexagonal close packing) has alternate layers positioned directly above/below each other: A,B,A,B,...
  • Cu type (face-centered cubic) has every third layer directly above/below each other: A,B,C,A,B,C,...
  • α-La type (double hexagonal close packing) has layers directly above/below each other, A,B,A,C,A,B,A,C,.... of period length 4 like an alternative mixture of fcc and hcp packing.[21]
  • α-Sm type has a period of 9 layers A,B,A,B,C,B,C,A,C,...[22]

Precisely speaking, the structures of many of the elements in the groups above are slightly distorted from the ideal closest packing. While they retain the lattice symmetry as the ideal structure, they often have nonideal c/a ratios for their unit cell. Less precisely speaking, there are also other elements are nearly close-packed but have distortions which have at least one broken symmetry with respect to the close-packed structure:

  • In type is slightly distorted from a cubic close packed structure
  • α-Pa type is distorted from a hexagonal close packed structure

See also

References

  1. .
  2. .
  3. .
  4. ^ .
  5. .
  6. .
  7. ^ .
  8. ^ .
  9. ^ Östlin, A. (2013). "Transition metals". Electronic Structure Studies and Method Development for Complex Materials (PDF) (Licentiate). pp. 15–16. Retrieved 24 October 2019.
  10. PMC 6916354
    .
  11. ^ Atarah, Samuel A.; Egblewogbe, Martin N. H.; Hagoss, Gebreyesus G. (2020). "First principle study of the structural and electronic properties of Nihonium". MRS Advances: 1–9. .
  12. ^ .
  13. ^ Lemire, R. J. et al.,2001
  14. ^ URL "The alpha-Pu Structure". Archived from the original on 2011-12-30. Retrieved 2012-02-05.
  15. ^ Lemire, R.J. et al.,Chemical Thermodynamics of Neptunium and Plutonium, Elsevier, Amsterdam, 2001
  16. ^ URL "The alpha Np (A_c) Structure". Archived from the original on 2012-10-02. Retrieved 2013-10-16.
  17. ^ Harry L. Yakel, A REVIEW OF X-RAY DIFFRACTION STUDIES IN URANIUM ALLOYS. The Physical Metallurgy of Uranium Alloys Conference, Vail, Colorado, Feb. 1974
  18. ^ .
  19. ^ A.F Wells (1962) Structural Inorganic Chemistry 3d Edition Oxford University Press
  20. ^ Nevill Gonalez Swacki & Teresa Swacka, Basic elements of Crystallography, Pan Standford Publishing Pte. Ltd., 2010
  21. ^ URL "The alpha la (A3') Structure". Archived from the original on 2011-12-23. Retrieved 2012-02-05.
  22. ^ URL "The alpha Sm (C19) Structure". Archived from the original on 2012-01-12. Retrieved 2012-02-05.
General

External links