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

C30H35N7O4S

Molecular formula

Molar mass589.71g/mol
Monoisotopic mass589.2471Da
Nominal mass589Da
Rings plus double bonds
17
Details
Monoisotopic mass
589.247124 Da
Average mass, unrounded
589.715000 g/molShown above to 2 decimals, the precision of the least precise standard atomic weight in the formula.
Mass defect
0.2471 Da
Atoms
77

Isotope pattern

M · C30H35N7O4S · most intense peak 589.2471

0255075100589.0589.5590.0590.5591.0591.5592.0592.5593.0593.5594.0594.5589.2471100%590.250036.3%591.248911.7%592.24962.62%%mass (Da)
IonFormulam/z
C30H35N7O4S 589.2471
C30H36N7O4S+ 590.2544
C30H35N7NaO4S+ 612.2363
C30H35KN7O4S+ 628.2103
C30H39N8O4S+ 607.2809
C30H37N7O4S2+ 295.6308
C30H35N7O4S+ 589.2466
C30H34N7O4S− 588.2398
C30H35ClN7O4S− 624.2165
Peak list
Mass (Da)Relative intensityAbundance
589.24712100.00 %66.1390 %
590.2499836.35 %24.0408 %
591.2489411.72 %7.7509 %
592.249552.62 %1.7359 %
593.250870.439 %0.2901 %
594.252510.058 %0.0386 %

Elemental composition

ElementAtomsMass (g/mol)Mass %
C Carbon30360.33061.10
H Hydrogen3535.2805.98
N Nitrogen798.04916.63
O Oxygen463.99610.85
S Sulfur132.0605.44

Elemental analysis

ElementCalcd (%)Found (%)Δ
C61.10——
H5.98——
N16.63——
S5.44——
Anal. Calcd for C30H35N7O4S: C, 61.10; H, 5.98; N, 16.63; S, 5.44.
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.