Formula composition and declared-weight mass
Calculate full element counts and per-element contributions from neutral formulas while preserving the explicitly selected decimal weight table and original source.
Declare the formula and weight source together
Enter one neutral formula per physical line, or choose a strict UTF-8 file. A selected file supplies the source; its BOM and CRLF/LF/CR bytes remain in original.txt. The report retains each nonblank formula and its exact source byte/character span after trimming only outer ASCII spaces and tabs.
CO2OHC5H18COO contains repeated symbols and a two-digit subscript. The full counts are C7, H19 and O5. In Custom mode paste symbol,weight with C,12.01; H,1.008; O,16 on separate rows. The exact declared total is 183.222.
- Choose the fixed molmass2026.8.15 table or Custom table explicitly.
- Custom replaces the whole table; every used element needs a unique positive weight. Unused valid rows stay in the exported table.
- Leave the custom field empty in fixed mode. Switching sources does not silently merge values.
Use the bounded neutral grammar
Symbols are case-sensitive ASCII elements H–Mt; positive integer counts have no leading zero. Parentheses and square brackets enclose nonempty nested groups. CuSO4·5H2O and CuSO4.5H2O both give Cu1/S1/O9/H10. A dot always separates hydrate components; H1.5 is not fractional hydrogen.
Charges, isotopes and D/T aliases, initial whole-formula coefficients, physical-state labels, expressions/macros/scripts and elements Ds–Og are outside this profile. Unknown symbols and malformed groups are rejected.
| Input | Meaning | Outcome |
|---|---|---|
| CO2OHC5H18COO | Repeated C/H/O tokens | Full C7/H19/O5 counts |
| K4[Fe(CN)6] | Nested neutral group | K4/Fe1/C6/N6 |
| CuSO4·5H2O | Hydrate delimiter followed by factor5 | Cu1/S1/O9/H10 |
| H1.5 | Hydrate component5 with no element | Rejected; no fractional-count interpretation |
| [13C]H4 / NH4+ | Isotope / charge | Unsupported |
Keep the table with the complete report
The fixed109-row table uses exact decimal mass= source literals from molmass2026.8.15, not reconstructed floating-point values. Its version, pinned source URL, SHA and BSD-3-Clause attribution accompany the data. Custom CSV is limited to an unquoted symbol,weight header and two fields per unique element row; weights are unsigned positive plain decimals, without exponent notation or leading zero.
The complete report preserves every formula, canonical atomic-number order, total atoms, each count/declared-weight/contribution and the complete chosen table. Normalized ordering is atomic-number order, so H19C7O5 is the canonical representation of the author example; the original spelling remains separate.
- original.txt preserves exact formula-file bytes.
- report.json and composition.csv contain all formulas and contributions.
- weight-table.csv contains every selected table row; custom mode also retains original-weights.csv.
- Import count and mass columns as text when spreadsheet software would round very large numbers.
Review limits and recover from an atomic refusal
Budgets apply together: formula input1MiB;10,000 formulas;4,096 UTF-8 bytes per formula;100,000 contributions;depth16;32 digits per count token;512 digits per intermediate element/atom count;500,000 work units;custom table16KiB/109 rows/6 integer and32 fractional digits;complete combined originals/JSON/CSV32MiB. This is not an arbitrary Cartesian-product promise.
The table previews200 contributions and2,000 UTF-16 units per long cell. Copy is a report preview above20,000 characters; full downloads stay complete. Errors and cancellation return no partial files. Correct the source or reduce complete work/input/output, then rerun the same supported original.
References
- Original formula and explicit-weight question
First-person demand: repeated elements and multi-digit subscripts, explicit weights; prose and code tables differ.
- Pinned molmass2026.8.15 element source
Correctness and data provenance only; exact mass keyword literals and full BSD-3-Clause source notice.
Tools in this category
Expand a tool to see its steps, options and supported formats, then open its workspace.
Formula composition and declared-weight massCount every repeated element in neutral formulas, then calculate each contribution and the total using a versioned weight table or your explicit decimal weights.
Choose the weight source before calculating. Exact decimal arithmetic preserves the declared numbers; it does not make them a sample-specific or isotopic physical mass.
Steps
- Enter one supported neutral formula per line or select a UTF-8 formula file. The selected file supplies the source.
- Select the versioned fixed table or Custom table; in Custom paste every used element and its positive decimal weight.
- Inspect the formula/contribution counts and weight source, then download the complete report, composition CSV, weight table and exact originals.
Available options
- Explicit weight source
- molmass2026.8.15 declared table · Custom decimal table
Custom replaces the complete table; there is no automatic fixed-table fallback. Clear the custom-weight field before returning to the fixed table.
Capabilities and limits
- Formula source: strict UTF-8, optional retained BOM, up to1MiB,10,000 nonblank physical lines and4,096 UTF-8 bytes per formula. Only outer ASCII spaces/tabs are trimmed. CRLF/LF/CR and byte/character source spans remain in the complete report.
- Exactly109 elements H–Mt; case-sensitive ASCII symbols, positive integer counts without leading zero, nonempty nested ()/[] up todepth16. Each count token≤32 digits; intermediate element/atom counts≤512 digits. Dot . or · is a hydrate separator with an optional positive factor after it, never decimal stoichiometry.
- Charges, isotope labels/D/T, initial coefficients, states/macros/expressions, fractional counts and Ds–Og are Unsupported. Unknown symbols, empty groups, zero/negative weights, duplicate or missing used weights are rejected atomically.
- Fixed table: molmass2026.8.15 exact source decimal literals,109 rows, source SHA and full BSD-3-Clause notice. Custom mode replaces the whole table without fallback: header symbol,weight and at most109 unique rows, unsigned positive plain decimals up to6 integer/32 fractional digits, strict unquoted two-field lines, total≤16KiB. Leave the custom field empty in fixed mode.
- At most100,000 element contributions and500,000 work units; all original files, JSON and CSV combined≤32MiB. Input, formula dimensions, count growth, work and output apply together; some combinations reach a guard before their other dimensions reach a maximum.
- The table shows the first200 contributions and first2,000 UTF-16 units per long cell. Copy is a report preview above20,000 characters; all downloads remain complete. Calculated sums are exact strings; importing CSV numbers into a spreadsheet may round them. Declared average/database values do not represent physical exact mass, isotope spectra or sample uncertainty.