Source: https://guthlabs.ai/docs/instruments/empirical-molecular-formula-finder/

instrument / verified-clean

# Empirical & Molecular Formula Finder

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/empirical-molecular-formula-finder/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/empirical-molecular-formula-finder/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/empirical-molecular-formula-finder/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/empirical-molecular-formula-finder/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Chemistry & Materials

**Tranche**: calibration-1

**Evidence ID**: offline/source boundary

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The core stoichiometric equations are standard, but the product is not fully specification-complete. The exact ambiguities requiring review are the ratio-rounding tolerance and multiplier-search policy, treatment of zero elements, percentage normalization and validation, and acceptance criteria for the molecular multiplier.

### Formula and scope findings

- moles=mass/M is correct only when mass and molar mass use compatible units; the specification does not state this explicitly.

- Dividing every mole value by the smallest is correct for nonzero elemental amounts, but the specification does not define how zero-valued elements are handled.

- multiply to whole-number ratio is underspecified: it needs a tolerance for recognizing near-integer ratios and a defined multiplier-search limit. Blind multiplication can produce incorrect formulas from rounded composition data.

- n=M_molecular/M_empirical is correct only when the result is a positive integer within a defined tolerance. The specification does not require molecular molar mass to be at least the empirical formula mass or reject noninteger results.

- The percent-composition workflow does not explicitly state that percentages are placed on a common 100-mass-unit basis and that the percentages should sum to approximately 100%.

### Unit assumptions

- Mass and molar mass must use compatible units, such as grams and grams per mole; any common mass unit is acceptable if used consistently.

- Percentage composition is interpreted as grams of each element in a 100 g sample, or an equivalent common mass basis.

- Atomic weights are dimensionless relative atomic masses used numerically in g/mol for molar-mass calculations.

- Empirical-formula recognition requires a rounding tolerance because measured or rounded composition data rarely produce exact integer ratios.

- The molecular molar mass input is assumed to be in g/mol and uses the same atomic-weight table as the empirical-formula mass.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

A zero-mass element produces a zero smallest-mole value and therefore undefined normalization; the instrument must reject it. Unit interpretation of molecular molar mass can also change the molecular formula by a factor of 1000 if not explicitly constrained.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "composition_type": "percent",
    "percent_composition": {
      "C": 40,
      "H": 6.71,
      "O": 53.29
    },
    "atomic_weights": {
      "C": 12.011,
      "H": 1.008,
      "O": 15.999
    },
    "molecular_molar_mass_g_per_mol": 180.156
  },
  "expected_outputs": {
    "empirical_formula": "CH2O",
    "molecular_formula": "C6H12O6",
    "ratio_table": {
      "C": 1,
      "H": 1.999,
      "O": 1
    },
    "empirical_molar_mass_g_per_mol": 30.026,
    "molecular_multiplier": 6
  },
  "working": "Use a 100 g basis: C moles = 40.00/12.011 = 3.33028; H moles = 6.71/1.008 = 6.65675; O moles = 53.29/15.999 = 3.33083. Divide by the smallest value, 3.33028: C = 1.00000; H = 6.65675/3.33028 = 1.99886, approximately 2; O = 3.33083/3.33028 = 1.00017, approximately 1. Empirical formula = CH2O. Empirical mass = 12.011 + (2 x 1.008) + 15.999 = 30.026 g/mol. Molecular multiplier = 180.156/30.026 = 6. Molecular formula = C6H12O6."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche2/batch10-output.jsonl`

- `BOUNDARY_HAZARD_CATALOG.json`