Alternative data storage structures were considered during the development the AIF, such as the comma-separated-value (CSV) file. The key, however, is that a universal data format must also include a well-structured record of metadata associated with the adsorption experiment. Without the metadata containing, at the very least, what gas or temperature was used during the experiment, the resulting adsorption data is meaningless. Metadata is also important in the development of databases. This is crucial to identify identical or related data, understand the evolution of databases over time, and also permit further examination for specific data items. As a result, the STAR data structure was adopted, which is famously used in crystallographic information file (CIF) and biological nuclear magnetic resonance experiments (NMR-STAR). An important property of the STAR format is that its syntax is defined by a few simple rules using an object/relational model. The data stored in a STAR file is self-descriptive as the underpinning data structure consists of tag-value pairs or data item. This data item is the combination of a data value with a data name, identified by a unique tag. This approach is flexible and is able to represent nested and repetitive data, which are particularly important for the collection of pressure and adsorbed amount data that comprise an adsorption isotherm experiment.