Given an elemental formula and the average relative atomic masses of the elements, determine the molecular weight.
a list describing the elemental formula. The allowed elements are C, H, N, O, S, P, Br, Cl, F, I, Si, Sn, and a user defined "x". See Examples.
a list specifing user defined standard atomic masses of the elements (in atomic mass units).
The user defined
x in the argument lists can be used to define an additional element, such as a metal. See example.
Due to apparent rounding differences at the elemental level, other sources of molecular weight information may vary in the second or third decimal place.
This function will accept values that do not correspond to known physical reality, such as a fractional number of elements or the wrong standard atomic mass for an element.
The molecular weight of the molecule.
Nathan G. Dodder
The relative atomic masses of the elements are from the NIST Physical Reference Data Website https://www.nist.gov/pml/atomic-weights-and-isotopic-compositions-relative-atomic-masses.
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MolecularWeight(formula = list(C=2, H=4)) ## Molecular weight of cyanocobalamin (C63H88CoN14O14P) with user defined cobalt MolecularWeight(formula = list(C=63, H=88, N=14, O=14, P=1, x=1), amu = list(x = 58.933200)) ## Molecular weight of triiodothyronine (C15H12I3NO4) using output from ListFormula MolecularWeight(formula = ListFormula("C15H12I3NO4"))
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