Molar mass

Molar mass, exact mass and elemental composition for any formula, compound or SMILES, with the isotope pattern, HRMS adducts and an elemental analysis check.

Formula or compound

Read as a formula
Examples:

Hydrates with · or *, charges as Fe3+ or SO4{2-}, labelled atoms as [13C] or D.

Molar mass

C32H33ClFN5O11

Molecular formula

Molar mass718.09g/mol
Monoisotopic mass717.1849Da
Nominal mass717Da
Rings plus double bonds
18
Details
Monoisotopic mass
717.184913 Da
Average mass, unrounded
718.088403 g/molShown above to 2 decimals, the precision of the least precise standard atomic weight in the formula.
Mass defect
0.1849 Da
Atoms
83

Isotope pattern

M · C32H33ClFN5O11 · most intense peak 717.1849

0255075100717718719720721722723724717.1849100%719.183941%718.188037.2%720.186013.5%721.18833.12%%mass (Da)
IonFormulam/z
C32H33ClFN5O11 717.1849
C32H34ClFN5O11+ 718.1922
C32H33ClFN5NaO11+ 740.1741
C32H33ClFKN5O11+ 756.1481
C32H37ClFN6O11+ 735.2187
C32H35ClFN5O112+ 359.5997
C32H33ClFN5O11+ 717.1844
C32H32ClFN5O11− 716.1776
C32H33Cl2FN5O11− 752.1543
Peak list
Mass (Da)Relative intensityAbundance
717.18491100.00 %51.1383 %
718.1880037.24 %19.0416 %
719.1838641.00 %20.9657 %
720.1860213.55 %6.9269 %
721.188263.12 %1.5972 %
722.190650.553 %0.2828 %
723.193040.081 %0.0415 %
724.195430.010 %0.0052 %

Elemental composition

ElementAtomsMass (g/mol)Mass %
C Carbon32384.35253.52
H Hydrogen3333.2644.63
Cl Chlorine135.4504.94
F Fluorine118.9982.65
N Nitrogen570.0359.75
O Oxygen11175.98924.51

Elemental analysis

ElementCalcd (%)Found (%)Δ
C53.52——
H4.63——
N9.75——
Anal. Calcd for C32H33ClFN5O11: C, 53.52; H, 4.63; N, 9.75.
How the masses are calculated

The molar mass sums the IUPAC standard atomic weights, using the conventional value for elements whose weight is given as an interval (hydrogen 1.008, carbon 12.011, sulfur 32.06). It is shown to the number of decimals of the least precise atomic weight in the formula, so CuSO4·5H2O gets two decimals because of sulfur; the unrounded value is under Details.

The monoisotopic mass uses the mass of the most abundant isotope of every element, the nominal mass its mass number. Labelled atoms, written [13C], D or T, count with their own nuclide mass and are taken as fully enriched. For an ion, one electron mass, 0.000 548 579 909 u, is subtracted per positive charge and added per negative charge.

How the isotope pattern is computed

Every element's natural isotope distribution is raised to its atom count by repeated squaring, and the element distributions are then convolved with each other. In centroid mode the isotopologues are grouped by nominal mass and each group is reported at its intensity-weighted mean m/z, which is what a mass spectrometer at ordinary resolution shows; this is exact apart from dropping contributions below 10−12 of the largest. Fine structure keeps isotopologues apart, merges those closer than 0.1 mDa and drops those below 10−8 of the largest, which resolves, for example, 34S from 13C2.

Adduct m/z values follow m/z = (M + adduct − z·me) / |z|. The copy button gives the line in the form the ACS journals print, for example “[M + H]+ Calcd for C8H11N4O2 195.0877”. The ACS guidelines ask that found and calculated m/z agree within 0.003 m/z units, the limit the found m/z check uses.

Elemental analysis

Calculated percentages are mass fractions from the standard atomic weights. Journals ask for found values within ±0.4 % (absolute) of the calculated ones. If a sample holds solvent, enter it as a solvate, for example 0.5 × H2O, and the calculated values are for C8H10N4O2·0.5H2O.

Sources

Standard atomic weights: IUPAC Commission on Isotopic Abundances and Atomic Weights, “Standard atomic weights of the elements 2021”, Pure Appl. Chem. 94, 573 (2022). Isotope masses and natural abundances: NIST, Atomic Weights and Isotopic Compositions for All Elements (Standard Reference Database 144). Electron mass: CODATA 2018, Rev. Mod. Phys. 93, 025010 (2021). Reporting criteria: ACS Author Guidelines for The Journal of Organic Chemistry and Organic Letters.