@ameyanagi/chemical-formula

WASM/Node.js bindings for the Rust chemical-formula parser.

Use this package to parse chemical formulas, convert between molecular and weight-percent representations, and calculate molecular weights. It supports ordinary formulas such as H2O, weight-percent annotations such as Pt5wt%/SiO2, and flexible catalyst loading notation such as 1%Pt/SiO2, Pt1%/SiO2, and 1wt%Pt@SiO2.

Installation

npm install @ameyanagi/chemical-formula

With Bun:

bun add @ameyanagi/chemical-formula

Quick Start

import {
  molecularWeight,
  parseFormula,
  toMolecularFormula,
  toWtPercent,
} from "@ameyanagi/chemical-formula";

const catalyst = parseFormula("1%Pt/SiO2");

console.log(catalyst);
// {
//   formula: "Pt1wt%O2Si",
//   elements: ["O", "Si", "Pt"],
//   stoichiometry: { O: 2, Si: 1 },
//   wt_percent: { Pt: 1 }
// }

const molecular = toMolecularFormula("1%Pt/SiO2");
console.log(molecular.stoichiometry.Pt);
// 0.0031109624054201776

const water = toWtPercent("H2O");
console.log(water.wt_percent);
// { H: 11.19067443796836, O: 88.80932556203165 }

console.log(molecularWeight("H2O"));
// 18.015

API

type FormulaSummary = {
  formula: string;
  elements: string[];
  stoichiometry: Record<string, number>;
  wt_percent: Record<string, number>;
};

• parseFormula(input: string): FormulaSummary
• toMolecularFormula(input: string): FormulaSummary
• toWtPercent(input: string): FormulaSummary
• molecularWeight(input: string): number

All parsing and conversion errors are thrown as JavaScript errors.

Supported Notation Examples

These examples all describe 1 wt% Pt on silica:

parseFormula("1%Pt/SiO2");
parseFormula("Pt1%/SiO2");
parseFormula("1wt%Pt/SiO2");
parseFormula("Pt1wt%/SiO2");
parseFormula("1wt%Pt@SiO2");
parseFormula("1 wt % Pt / SiO2");

Bare % is interpreted as wt%.

Nested materials are supported:

const composite = toWtPercent("(Pt5wt%/SiO2)50wt%(CeO2)50wt%");

console.log(composite.wt_percent.Pt);
// 2.5000000000000004

Package Notes

This package is generated from the Rust crate with wasm-pack and targets Node.js-compatible runtimes.