v2.0.1 — Fixed a huge bug

Precise electrolyte
thermodynamics,
computed live.

Aqueous speciation, phase equilibrium, and activity coefficients — from ambient conditions to hydrothermal extremes, backed by a citation-traced database.

Start computing →View documentation

12k+species

340+electrolytes

18calc tools

1000°Cmax temp

Activity coefficient — NaCl(aq)γ± = f(A, B, b·, I)

ionic strength I0.250

γ± mean activity0.719

modelExt. Debye–Hückel (B-dot)

Who it's for

One workspace, three kinds of work.

Geochemists & hydrogeologists

Speciate natural waters, model water–rock interaction, and predict mineral solubility from cold groundwater to 1000 °C hydrothermal fluids.

Process & materials engineers

Screen scaling, corrosion, and precipitation risk in industrial brines, desalination trains, and mineral-processing streams before they reach the plant.

Researchers & educators

Run reproducible, citation-linked calculations for papers and coursework — every parameter in the database traces back to its primary source.

How it works

Input → results → a
report you can cite.

Define conditions & species

Structured input with formula search, phase badges, and real-time species suggestions.

Solve to convergence

Editable, spreadsheet-style results with residual diagnostics and CSV export.

Export a cited report

Auto-generated citations to primary literature, plus a resizable panel for interactive plots.

InputResultsReport

Conditions

25.0°C

0.101MPa

Results

Activity coefficientsConverged

Speciesγ±log γm mol/kg

Na⁺0.6813−0.1670.5000

Cl⁻0.6571−0.1820.5000

Ca²⁺0.2981−0.5260.0250

SO₄²⁻0.1563−0.8060.0125

Theoretical foundation

Built on the equations that hold at your conditions.

Activity models are regime-specific — the wrong one quietly gives you a confident, wrong answer. ChimiHub groups implementations by where they're actually valid.

Dilute

Dilute solutions

I ≲ 0.5 mol/kg

Debye–Hückel

Extended law and B-dot variant for low-ionic-strength waters.

log γᵢ = −Azᵢ²√I / (1 + Båᵢ√I)

SIT in development

Specific Ion Interaction Theory — NEA/OECD convention for radionuclide speciation.

Concentrated

Concentrated electrolytes

I up to ~6 mol/kg

Pitzer (1973)

Virial equation of state with β⁽⁰⁾, β⁽¹⁾, β⁽²⁾, C^φ interaction parameters.

ln γ± = f(I) + Σ B·m + Σ C·m²

PSC

Pitzer–Simonson–Clegg extension for mixed-solvent electrolytes.

High T / P

Hydrothermal fluids

0–1000 °C, 1–5000 bar

HKF / SUPCRT

Helgeson–Kirkham–Flowers EOS — SUPCRT92 & SUPCRTBL parameter sets.

ΔG° = ΔG°f + ω(1/ε − 1)

Driesner NaCl–H₂O new

Halite saturation, phase boundaries, and PVTX behavior of the reference brine system.

Fluids & water properties:

Peng–RobinsonSRK + PénelouxIAPWS-95 / IF97viscosity · dielectric · conductivity · tension

Reference data

A curated database you can trust.

Every species, reaction, and parameter traces back to a peer-reviewed source, and is continuously reviewed against primary literature.

Deterministic UUIDs — uniquely identified by formula, phase, charge & variant
CAS, SMILES, InChI & InChIKey identifiers stored for every species
Species–tool support registry links every entry to available methods
Full review workflow — draft → pending → approved status tracking

12^k

Species

4^k+

Reactions

340⁺

Electrolytes

Phases

Supported phases

Aqueous

Gas

Crystal

Liquid

Amorphous

vit

Vitreous

Supercrit.

Plasma

Species coverage over time

Cumulative approved species by approval date, grouped by week, and species with a complete standard-state property set (ΔfG°, ΔfH°, S°, V°, Cp°) from a single source. Older imports without a recorded approval date are included as the baseline (2 species).

Approved speciesComplete properties

Loading chart…

Live from the database

The full Alchemy tree, one click away.

Equilibrium

Properties

Transport

Databases

Ready to compute?

No license request, no configuration — the database is open to browse.

Open the workspace →Read the docs

Precise electrolytethermodynamics,computed live.