Source: https://guthlabs.ai/docs/instruments/vsepr-geometry-predictor/implementation/

instrument implementation / implementation-contract

# VSEPR Geometry Predictor implementation

A source-bound implementation contract for VSEPR Geometry Predictor; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-135

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification exposes invalid-input hazards at zero and at overflowing magnitudes, where a robust implementation must reject the input rather than perform an unchecked lookup. It also has a material convention hazard because VSEPR counts bonding domains, whereas the label 'bonding pairs' can be interpreted as individual shared electron pairs.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "central_atom": "C",
    "ligands": "O=C=O",
    "bonding_domains": 2,
    "lone_pairs": 0
  },
  "expected_outputs": {
    "steric_number": 2,
    "electron_geometry": "linear",
    "molecular_geometry": "linear",
    "idealized_bond_angles_deg": [
      180
    ]
  },
  "working": "Step 1: Count bonding domains: the two C–O directions give 2 domains; each C=O double bond still counts as one domain. Step 2: Add lone pairs: steric number = 2 + 0 = 2. Step 3: Steric number 2 maps to linear electron geometry. With no lone pairs, molecular geometry is also linear. Step 4: The ideal linear angle is 180°."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/vsepr-geometry-predictor/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/vsepr-geometry-predictor/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/vsepr-geometry-predictor/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`