# Chemical Elements API > The complete periodic table as an API — all 119 chemical elements with their atomic and physical properties: atomic number and mass, category, phase, melting and boiling point, density, electron configuration, electronegativity, ionization energies and a short summary. Look up an element by symbol, atomic number or name, search and filter by category/phase/block, or fetch the whole table. Ideal for chemistry tools, education apps and science projects. ## Authentication All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys. ```bash curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/elements-api/..." ``` ## Pricing - **Free** (Free) — 1,500 calls/Mo, 3 req/s - **Starter** ($4/Mo) — 30,000 calls/Mo, 8 req/s - **Pro** ($13/Mo) — 200,000 calls/Mo, 20 req/s - **Mega** ($37/Mo) — 1,200,000 calls/Mo, 40 req/s ## Endpoints ### Elements #### `GET /v1/element` — A single element by symbol, number or name **Parameters:** - `symbol` (query, optional, string) — Element symbol, e.g. Au Example: `Au` - `number` (query, optional, string) — Atomic number (1-118) - `name` (query, optional, string) — Element name, e.g. Gold **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/elements-api/v1/element?symbol=Au" ``` **Response:** ```json { "data": { "_hay": "gold au transition metal", "boil": 3243, "melt": 1337.33, "name": "Gold", "block": "d", "group": 11, "phase": "Solid", "number": 79, "period": 6, "shells": [ 2, 8, 18, 32, 18, 1 ], "source": "https://en.wikipedia.org/wiki/Gold", "symbol": "Au", "cpk_hex": "ffd123", "density": 19.3, "summary": "Gold is a chemical element with symbol Au (from Latin:aurum) and atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable and ductile metal. Chemically, gold is a transition metal and a group 11 element.", "category": "transition metal", "named_by": null, "appearance": "metallic yellow", "molar_heat": 25.418, "atomic_mass": 196.9665695, "discovered_by": "Middle East", "electron_affinity": 222.747, "ionization_energies": [ 890.1, 1980 ], "electron_configuration": "1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s1 4f14 5d10", "electronegativity_pauling": 2.54, "electron_configuration_semantic": "[Xe] 4f14 5d10 6s1" }, "meta": { "timestamp": "2026-05-31T01:12:18.057Z", "request_id": "f5ea8f70-d6da-4e0a-a8b8-b81929b415d8" }, "status": "ok", "message": "Element retrieved", …(truncated, see openapi.json for full schema) ``` #### `GET /v1/list` — The whole periodic table (lean) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/elements-api/v1/list" ``` **Response:** ```json { "data": { "count": 119, "elements": [ { "name": "Hydrogen", "phase": "Gas", "number": 1, "symbol": "H", "category": "diatomic nonmetal", "atomic_mass": 1.008 }, { "name": "Helium", "phase": "Gas", "number": 2, "symbol": "He", "category": "noble gas", "atomic_mass": 4.0026022 }, { "name": "Lithium", "phase": "Solid", "number": 3, "symbol": "Li", "category": "alkali metal", "atomic_mass": 6.94 }, { "name": "Beryllium", "phase": "Solid", "number": 4, "symbol": "Be", "category": "alkaline earth metal", "atomic_mass": 9.01218315 }, { "name": "Boron", "phase": "Solid", "number": 5, "symbol": "B", "category": "metalloid", "atomic_mass": 10.81 }, { "name": "Carbon", "phase": "Solid", "number": 6, "symbol": "C", "category": "polyatomic nonmetal", "atomic_mass": 12.011 …(truncated, see openapi.json for full schema) ``` #### `GET /v1/search` — Search & filter elements **Parameters:** - `q` (query, optional, string) — Name/symbol/category text Example: `gas` - `category` (query, optional, string) — Element category, e.g. noble gas - `phase` (query, optional, string) — Phase at STP: Solid, Liquid or Gas - `block` (query, optional, string) — Block: s, p, d or f - `limit` (query, optional, string) — Max results (1-118, default 30) Example: `30` **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/elements-api/v1/search?q=gas&limit=30" ``` **Response:** ```json { "data": { "count": 7, "total": 7, "filters": { "q": "gas", "block": null, "phase": null, "category": null }, "results": [ { "name": "Helium", "phase": "Gas", "number": 2, "symbol": "He", "category": "noble gas", "atomic_mass": 4.0026022 }, { "name": "Neon", "phase": "Gas", "number": 10, "symbol": "Ne", "category": "noble gas", "atomic_mass": 20.17976 }, { "name": "Argon", "phase": "Gas", "number": 18, "symbol": "Ar", "category": "noble gas", "atomic_mass": 39.9481 }, { "name": "Krypton", "phase": "Gas", "number": 36, "symbol": "Kr", "category": "noble gas", "atomic_mass": 83.7982 }, { "name": "Xenon", "phase": "Gas", "number": 54, "symbol": "Xe", "category": "noble gas", "atomic_mass": 131.2936 }, { "name": "Radon", "phase": "Gas", "num …(truncated, see openapi.json for full schema) ``` ### Meta #### `GET /v1/meta` — Categories, phases, blocks & source **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/elements-api/v1/meta" ``` **Response:** ```json { "data": { "total": 119, "blocks": [ "d", "f", "p", "s" ], "fields": [ "name", "symbol", "number", "atomic_mass", "category", "phase", "period", "group", "block", "melt", "boil", "density", "molar_heat", "electronegativity_pauling", "electron_affinity", "ionization_energies", "electron_configuration", "electron_configuration_semantic", "shells", "appearance", "discovered_by", "named_by", "summary", "source", "cpk_hex" ], "phases": [ "Gas", "Liquid", "Solid" ], "source": "Periodic-Table-JSON (Bowserinator)", "categories": [ "actinide", "alkali metal", "alkaline earth metal", "diatomic nonmetal", "lanthanide", "metalloid", "noble gas", "polyatomic nonmetal", "post-transition metal", "transition metal", "unknown, but predicted to be an alkali metal", "unknown, predicted to be noble gas", "unknown, probably metalloid", "unknown, probably post-transition metal", …(truncated, see openapi.json for full schema) ``` --- Marketplace page: https://www.oanor.com/api/elements-api OpenAPI spec: https://www.oanor.com/api/elements-api/openapi.json