# Basic usage

The periodic table is available on PyPI, and can be obtained simply with:

    easy_install periodictable

This will install pyparsing if it is not already available. The numpy package must already be installed.

Access particular elements by name:

    >>> from periodictable import hydrogen
    >>> print("H mass %s %s"%(hydrogen.mass, hydrogen.mass_units))
    H mass 1.00794 u

Access particular elements as symbols:

    >>> from periodictable import H,B,Cu,Ni
    >>> print("B absorption %s"%B.neutron.absorption)
    B absorption 767.0
    >>> print("Ni f1/f2 for Cu K-alpha X-rays %s"%str(Ni.xray.scattering_factors(wavelength=Cu.K_alpha)))
    Ni f1/f2 for Cu K-alpha X-rays (25.022929905648375, 0.52493074546535157)

Access isotopes using mass number subscripts:

    >>> print("58-Ni vs 62-Ni scattering %s:%s"%(Ni[58].neutron.coherent, Ni[62].neutron.coherent))
    58-Ni vs 62-Ni scattering 26.1:9.5

Access elements indirectly:

    >>> import periodictable
    >>> print("Cd density %.2f %s"%(periodictable.Cd.density, periodictable.Cd.density_units))
    Cd density 8.65 g/cm^3

Import all elements:

    >>> from periodictable import *
    >>> print(periodictable.H)
    H
    >>> print(periodictable.H.mass)
    1.00794

Deuterium and tritium are special isotopes named D and T some neutron information is available as ‘n’:

    >>> print("D mass %s"%D.mass)
    D mass 2.014101778
    >>> print("neutron mass %s"%n.mass)
    neutron mass 1.00866491597

Process all the elements:

    >>> import periodictable
    >>> for el in periodictable.elements:
    ...     print("%s %s"%(el.symbol,el.name))
    n neutron
    H hydrogen
    He helium
       ...
    Og oganesson

Another example for processing all elements:

    >>> from periodictable import elements
    >>> for el in elements:
    ...     print("%s %s"%(el.symbol,el.number))
    n 0
    H 1
    He 2
       ...

Process all the `isotopes` for an element:

    >>> for iso in periodictable.H:
    ...     print("%s %s"%(iso,iso.mass))
    1-H 1.0078250321
    D 2.014101778
    T 3.0160492675
    4-H 4.02783
    5-H 5.03954
    6-H 6.04494

You can create a unique handle to an individual ion. In addition to storing the ion charge, this can be used to reference the underlying properties of the element or isotope:

    >>> Ni58_2 = periodictable.Ni[58].ion[2]
    >>> Ni_2 = periodictable.Ni.ion[2]
    >>> print("charge for Ni2+ is %d"%Ni_2.charge)
    charge for Ni2+ is 2
    >>> print("mass for Ni[58] and for natural abundance: %.4f %.4f"%(Ni58_2.mass, Ni_2.mass))
    mass for Ni[58] and for natural abundance: 57.9343 58.6923

The ion specific properties can be accessed from the ion using ion.charge for the ion index:

    >>> import pylab
    >>> import periodictable
    >>> Fe_2 = periodictable.Fe.ion[2]
    >>> print(Fe_2.magnetic_ff[Fe_2.charge].M_Q([0,0.1,0.2]))
    [ 1.          0.99935255  0.99741366]

The following is a plot of the magnetic form factor vs. Q:

    >>> Q = pylab.linspace(0,16,200)
    >>> M = Fe_2.magnetic_ff[Fe_2.charge].j0_Q(Q)
    >>> pylab.xlabel(r'Magnetic Form Factor for Fe')
    >>> pylab.ylabel(r'$\AA^{-1}$')
    >>> pylab.title('Ion specific property for Fe')
    >>> pylab.plot(Q,M)

(Source code, png, hires.png, pdf)

Missing properties generally evaluate to None:

    >>> print("Radon density %s"%periodictable.Rn.density)
    Radon density None

Specific defined properties related to elements can be accessed in a table format as shown in following example :

    >>> elements.list('symbol','K_alpha',format="%s K-alpha = %s")
    Ne K-alpha = 14.6102
    Na K-alpha = 11.9103
    Mg K-alpha = 9.8902
    Al K-alpha = 8.3402
       ...
    Cf K-alpha = 0.1094
    Es K-alpha = 0.1067
    Fm K-alpha = 0.104