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

C22H30N6O4S

Molecular formula

Molar mass474.58g/mol
Monoisotopic mass474.2049Da
Nominal mass474Da
Rings plus double bonds
11
Details
Monoisotopic mass
474.204925 Da
Average mass, unrounded
474.580000 g/molShown above to 2 decimals, the precision of the least precise standard atomic weight in the formula.
Mass defect
0.2049 Da
Atoms
63

Isotope pattern

M · C22H30N6O4S · most intense peak 474.2049

0255075100474475476477478479474.2049100%475.207727.3%476.20548.88%477.20641.71%%mass (Da)
IonFormulam/z
C22H30N6O4S 474.2049
C22H31N6O4S+ 475.2122
C22H30N6NaO4S+ 497.1941
C22H30KN6O4S+ 513.1681
C22H34N7O4S+ 492.2388
C22H32N6O4S2+ 238.1097
C22H30N6O4S+ 474.2044
C22H29N6O4S− 473.1976
C22H30ClN6O4S− 509.1743
Peak list
Mass (Da)Relative intensityAbundance
474.20492100.00 %72.3881 %
475.2077027.27 %19.7428 %
476.205438.88 %6.4277 %
477.206381.71 %1.2384 %
478.207690.249 %0.1799 %
479.209300.029 %0.0209 %

Elemental composition

ElementAtomsMass (g/mol)Mass %
C Carbon22264.24255.68
H Hydrogen3030.2406.37
N Nitrogen684.04217.71
O Oxygen463.99613.48
S Sulfur132.0606.76

Elemental analysis

ElementCalcd (%)Found (%)Δ
C55.68——
H6.37——
N17.71——
S6.76——
Anal. Calcd for C22H30N6O4S: C, 55.68; H, 6.37; N, 17.71; S, 6.76.
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.