molecular weight

[longemen3000]

one way to obtain all the molecular weights in a programmatic way:

using PeriodicTables, Unitful
a = PeriodicTables._element_data
mw  = map(x->ustrip(x.atomic_mass),values(a))
names = map(x->x.symbol,values(a))
molecular_weights= Dict{String,Float64}(Iterators.zip(names,mw))

without depending on PeriodicTables or unitful, the data is the following:

H => 1.008,
He => 4.0026022,
Li => 6.94,
Be => 9.01218315,
B => 10.81,
C => 12.011,
N => 14.007,
O => 15.999,
F => 18.9984031636,
Ne => 20.17976,
Na => 22.989769282,
Mg => 24.305,
Al => 26.98153857,
Si => 28.085,
P => 30.9737619985,
S => 32.06,
Cl => 35.45,
Ar => 39.9481,
K => 39.09831,
Ca => 40.0784,
Sc => 44.9559085,
Ti => 47.8671,
V => 50.94151,
Cr => 51.99616,
Mn => 54.9380443,
Fe => 55.8452,
Co => 58.9331944,
Ni => 58.69344,
Cu => 63.5463,
Zn => 65.382,
Ga => 69.7231,
Ge => 72.6308,
As => 74.9215956,
Se => 78.9718,
Br => 79.904,
Kr => 83.7982,
Rb => 85.46783,
Sr => 87.621,
Y => 88.905842,
Zr => 91.2242,
Nb => 92.906372,
Mo => 95.951,
Tc => 98.0,
Ru => 101.072,
Rh => 102.905502,
Pd => 106.421,
Ag => 107.86822,
Cd => 112.4144,
In => 114.8181,
Sn => 118.7107,
Sb => 121.7601,
Te => 127.603,
I => 126.904473,
Xe => 131.2936,
Cs => 132.905451966,
Ba => 137.3277,
La => 138.905477,
Ce => 140.1161,
Pr => 140.907662,
Nd => 144.2423,
Pm => 145.0,
Sm => 150.362,
Eu => 151.9641,
Gd => 157.253,
Tb => 158.925352,
Dy => 162.5001,
Ho => 164.930332,
Er => 167.2593,
Tm => 168.934222,
Yb => 173.0451,
Lu => 174.96681,
Hf => 178.492,
Ta => 180.947882,
W => 183.841,
Re => 186.2071,
Os => 190.233,
Ir => 192.2173,
Pt => 195.0849,
Au => 196.9665695,
Hg => 200.5923,
Tl => 204.38,
Pb => 207.21,
Bi => 208.980401,
Po => 209.0,
At => 210.0,
Rn => 222.0,
Fr => 223.0,
Ra => 226.0,
Ac => 227.0,
Th => 232.03774,
Pa => 231.035882,
U => 238.028913,
Np => 237.0,
Pu => 244.0,
Am => 243.0,
Cm => 247.0,
Bk => 247.0,
Cf => 251.0,
Es => 252.0,
Fm => 257.0,
Md => 258.0,
No => 259.0,
Lr => 266.0,
Rf => 267.0,
Db => 268.0,
Sg => 269.0,
Bh => 270.0,
Hs => 269.0,
Mt => 278.0,
Ds => 281.0,
Rg => 282.0,
Cn => 285.0,
Nh => 286.0,
Fl => 289.0,
Mc => 289.0,
Lv => 293.0,
Ts => 294.0,
Og => 294.0,
Uue => 315.0,

the method of extraction was the following:

for (k,v) in Iterators.zip(nam,w)
print(k)
print(" => ")
print(v)
println(",")
end

to extract the molecular weight, it suffices to make a dict with this data and call it. but im not familiarized enough with the API to do a pull request

[zlatanvasovic]

Even though it's another dependency, I'd rather depend on PeriodicTable, so that I don't have to maintain a knowledge base here. Maybe just generate the list once and store as const? PeriodicTable can also be used for other things, like validating do all elements in a compound string exist in the periodic table.

The best way to add molecular weight into API is just to define a method, since by default compound string can be anything and may not be valid for periodic table.

function molecularweight(compound::Compound)
    weight = 0
    for (element, k) in elementtuples
       weight += k * getweight_fromtable(element)
    end
    return weight
end

There may be a nice way to do further calculations, i.e. check "The chemical composition matrix" at http://logical.ai/chemistry/html/chem-nullspace.html. To get a specific number of moles of some compound, you can use matrix multiplication. Then you just multiply that number by molecular weight, and voila!

[longemen3000]

PeriodicTables.jl is basically a big Dict of elements haahah, but depends of unitful, and he molecular weights have units there.

[longemen3000]

to add to the method (in case someone needs it)

function molecularweight(compound::Compound)
    weight = 0.0
    for (element, k) in compound.tuples
       weight += k * getweight_fromtable(element)
    end
    weight +=  0.000548597*compound.charge #electrons weight something
end