What is MIME type "chemical/x-cml"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

chemical/x-cml is the MIME type for files using the Chemical Markup Language. It is an XML-based standard that holds chemical structure data. Data like atom positions, bonds, and reactions are stored in a structured text format.

This MIME type helps programs exchange and store rich chemical information. It is used for practical tasks such as:

Exchanging data between chemical software systems
Storing detailed molecular structure information
Integrating chemical datasets into research databases
Supporting computational chemistry and modeling applications

Files using this format carry the extension CML. The open, text-based design allows both machines and people to read and manage the chemical data easily.

For more technical details on Chemical Markup Language, visit this external reference.

Associated file extensions

.cml

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: chemical/x-cml

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="chemical/x-cml">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');
    
    http.createServer((req, res) => {
      res.setHeader('Content-Type', 'chemical/x-cml');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.cml

FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.