Extensible Markup Language (XML)

XML- Extensible Markup Language

- was designed to describe data and focus what data is.
- XML's design goals emphasize simplicity, generality, and usability over the internet.
- Although the design of XML focuses on documents, it is widely used for the representation of arbitrary data structures, for example in web services.
- is a markup language much like HTML.
- tags are not predefined.

1) XML syntax



2) XML tree




3) XML table

Computational method:

Method	Molecular mechanics	Semi empirical	Ab initio
Speed	Very fast speed	Fast speed	Slow speed
Accuracy	Parameter restriction	Good accuracy	Very good accuracy