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# This program is in the public domain
'''
Crystal structure data.
Adds *crystal_structure* to the periodic table. Each crystal structure
is a dictionary which contains the key 'symmetry'. Depending on the
value of crystal_structure['symmetry'], one or more parameters
'a', 'c/a', 'b/a', 'd', and 'alpha' may be present according to
the following table:
.. table:: Crystal lattice parameters
============ ===========
Symmetry Parameters
============ ===========
atom
diatom d
BCC a
fcc a
hcp c/a, a
Tetragonal c/a, a
Cubic a
Diamond a
Orthorhombic c/a, a, b/a
Rhombohedral a, alpha
SC a
Monoclinic
============ ===========
Example:
.. doctest::
>>> import periodictable as elements
>>> print(elements.C.crystal_structure['symmetry'])
Diamond
>>> print(elements.C.crystal_structure['a'])
3.57
This data is from Ashcroft and Mermin.
'''
crystal_structures = [\
{'symmetry': 'diatom', 'd': 0.74}, #H
{'symmetry': 'atom'}, #He
{'symmetry': 'BCC', 'a': 3.49}, #Li
{'symmetry': 'hcp', 'c/a': 1.567, 'a': 2.29}, #Be
{'symmetry': 'Tetragonal', 'c/a': 0.576, 'a': 8.73}, #B
{'symmetry': 'Diamond', 'a': 3.57}, #C
{'symmetry': 'diatom', 'd': 1.10}, #N
{'symmetry': 'diatom', 'd': 1.21}, #O
{'symmetry': 'diatom', 'd': 1.42}, #F
{'symmetry': 'fcc', 'a': 4.43}, #Ne
{'symmetry': 'BCC', 'a': 4.23}, #Na
{'symmetry': 'hcp', 'c/a': 1.624, 'a': 3.21}, #Mg
{'symmetry': 'fcc', 'a': 4.05}, #Al
{'symmetry': 'Diamond', 'a': 5.43}, #Si
{'symmetry': 'Cubic', 'a': 7.17}, #P
{'symmetry': 'Orthorhombic', 'c/a': 2.339, 'a': 10.47, 'b/a': 1.229}, #S
{'symmetry': 'Orthorhombic', 'c/a': 1.324, 'a': 6.24, 'b/a': 0.718}, #Cl
{'symmetry': 'fcc', 'a': 5.26}, #Ar
{'symmetry': 'BCC', 'a': 5.23}, #K
{'symmetry': 'fcc', 'a': 5.58}, #Ca
{'symmetry': 'hcp', 'c/a': 1.594, 'a': 3.31}, #Sc
{'symmetry': 'hcp', 'c/a': 1.588, 'a': 2.95}, #Ti
{'symmetry': 'BCC', 'a': 3.02}, #V
{'symmetry': 'BCC', 'a': 2.88}, #Cr
{'symmetry': 'Cubic', 'a': 8.89}, #Mn
{'symmetry': 'BCC', 'a': 2.87}, #Fe
{'symmetry': 'hcp', 'c/a': 1.622, 'a': 2.51}, #Co
{'symmetry': 'fcc', 'a': 3.52}, #Ni
{'symmetry': 'fcc', 'a': 3.61}, #Cu
{'symmetry': 'hcp', 'c/a': 1.856, 'a': 2.66}, #Zn
{'symmetry': 'Orthorhombic', 'c/a': 1.695, 'a': 4.51, 'b/a': 1.001}, #Ga
{'symmetry': 'Diamond', 'a': 5.66}, #Ge
{'symmetry': 'Rhombohedral', 'a': 4.13, 'alpha': 54.10}, #As
{'symmetry': 'hcp', 'c/a': 1.136, 'a': 4.36}, #Se
{'symmetry': 'Orthorhombic', 'c/a': 1.307, 'a': 6.67, 'b/a': 0.672}, #Br
{'symmetry': 'fcc', 'a': 5.72}, #Kr
{'symmetry': 'BCC', 'a': 5.59}, #Rb
{'symmetry': 'fcc', 'a': 6.08}, #Sr
{'symmetry': 'hcp', 'c/a': 1.571, 'a': 3.65}, #Y
{'symmetry': 'hcp', 'c/a': 1.593, 'a': 3.23}, #Zr
{'symmetry': 'BCC', 'a': 3.30}, #Nb
{'symmetry': 'BCC', 'a': 3.15}, #Mo
{'symmetry': 'hcp', 'c/a': 1.604, 'a': 2.74}, #Tc
{'symmetry': 'hcp', 'c/a': 1.584, 'a': 2.70}, #Ru
{'symmetry': 'fcc', 'a': 3.80}, #Rh
{'symmetry': 'fcc', 'a': 3.89}, #Pd
{'symmetry': 'fcc', 'a': 4.09}, #Ag
{'symmetry': 'hcp', 'c/a': 1.886, 'a': 2.98}, #Cd
{'symmetry': 'Tetragonal', 'c/a': 1.076, 'a': 4.59}, #In
{'symmetry': 'Tetragonal', 'c/a': 0.546, 'a': 5.82}, #Sn
{'symmetry': 'Rhombohedral', 'a': 4.51, 'alpha': 57.60}, #Sb
{'symmetry': 'hcp', 'c/a': 1.330, 'a': 4.45}, #Te
{'symmetry': 'Orthorhombic', 'c/a': 1.347, 'a': 7.27, 'b/a': 0.659}, #I
{'symmetry': 'fcc', 'a': 6.20}, #Xe
{'symmetry': 'BCC', 'a': 6.05}, #Cs
{'symmetry': 'BCC', 'a': 5.02}, #Ba
{'symmetry': 'hcp', 'c/a': 1.619, 'a': 3.75}, #La
{'symmetry': 'fcc', 'a': 5.16}, #Ce
{'symmetry': 'hcp', 'c/a': 1.614, 'a': 3.67}, #Pr
{'symmetry': 'hcp', 'c/a': 1.614, 'a': 3.66}, #Nd
None, #Pm
{'symmetry': 'Rhombohedral', 'a': 9.00, 'alpha': 23.13}, #Sm
{'symmetry': 'BCC', 'a': 4.61}, #Eu
{'symmetry': 'hcp', 'c/a': 1.588, 'a': 3.64}, #Gd
{'symmetry': 'hcp', 'c/a': 1.581, 'a': 3.60}, #Th
{'symmetry': 'hcp', 'c/a': 1.573, 'a': 3.59}, #Dy
{'symmetry': 'hcp', 'c/a': 1.570, 'a': 3.58}, #Ho
{'symmetry': 'hcp', 'c/a': 1.570, 'a': 3.56}, #Er
{'symmetry': 'hcp', 'c/a': 1.570, 'a': 3.54}, #Tm
{'symmetry': 'fcc', 'a': 5.49}, #Yb
{'symmetry': 'hcp', 'c/a': 1.585, 'a': 3.51}, #Lu
{'symmetry': 'hcp', 'c/a': 1.582, 'a': 3.20}, #Hf
{'symmetry': 'BCC', 'a': 3.31}, #Ta
{'symmetry': 'BCC', 'a': 3.16}, #W
{'symmetry': 'hcp', 'c/a': 1.615, 'a': 2.76}, #Re
{'symmetry': 'hcp', 'c/a': 1.579, 'a': 2.74}, #Os
{'symmetry': 'fcc', 'a': 3.84}, #Ir
{'symmetry': 'fcc', 'a': 3.92}, #Pt
{'symmetry': 'fcc', 'a': 4.08}, #Au
{'symmetry': 'Rhombohedral', 'a': 2.99, 'alpha': 70.45}, #Hg
{'symmetry': 'hcp', 'c/a': 1.599, 'a': 3.46}, #Tl
{'symmetry': 'fcc', 'a': 4.95}, #Pb
{'symmetry': 'Rhombohedral', 'a': 4.75, 'alpha': 57.14}, #Bi
{'symmetry': 'SC', 'a': 3.35}, #Po
None, #At
None, #Rn
None, #Fr
None, #Ra
{'symmetry': 'fcc', 'a': 5.31}, #Ac
{'symmetry': 'fcc', 'a': 5.08}, #Th
{'symmetry': 'Tetragonal', 'c/a': 0.825, 'a': 3.92}, #Pa
{'symmetry': 'Orthorhombic', 'c/a': 2.056, 'a': 2.85, 'b/a': 1.736}, #U
{'symmetry': 'Orthorhombic', 'c/a': 1.411, 'a': 4.72, 'b/a': 1.035}, #Np
{'symmetry': 'Monoclinic'}, #Pu
None, #Am
None, #Cm
None, #Bk
None, #Cf
None, #Es
None, #Fm
None, #Md
None, #No
None]#Lw
def init(table, reload=False):
"""
Add crystal_structure field to the element properties.
"""
if 'crystal_structure' in table.properties and not reload:
return
table.properties.append('crystal_structure')
for k, struct in enumerate(crystal_structures):
table[k+1].crystal_structure = struct
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