> For the complete documentation index, see [llms.txt](https://chembl.gitbook.io/unichem/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chembl.gitbook.io/unichem/web-application/formatting-of-input-data-for-unichem-queries..md).
# Query field requirements
Below are some simple tips for reviewing your query strings for the correct formatting
#### **src\_compound\_id**
src\_compound\_ids are treated in a case sensitive manner. For example, querying with 'chembl123' instead of 'CHEMBL123' will return nothing, as the lower-case form is currently not a valid ChEMBL id.
This distinction is made in UniChem to account for the possibility that a source may change the case in an src\_compound\_id from one release to another: UniChem must distinguish between these to indicate the current and obsolete versions to the user.
#### **src\_id**
src\_ids are integers.
#### **InChIs and InChIKeys**
Standard InChIs in UniChem are calculated with version 1 of the IUPAC International Chemical Identifier (InChI) generation software. Full detailed information of the format of valid Standard InChIs and InChIKeys using this software may be found [here](http://old.iupac.org/inchi/release102final.html) . Below are some simple first pass checks you can do before consulting the more detailed documentation cited in the above link.
#### **Standard InChIs**
Standard InChIs in UniChem should always begin with "**InChI=1S/".**
Thus, for example, the following string is a valid Standard InChi in UniChem.:
* **InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3**
#### **Standard InChIKeys**
Standard InChIKeys should always follow the following 27-character format...
* **XXXXXXXXXXXXXX-XXXXXXXXSA-X**
* X is any uppercase letter
* The two hyphens separate three blocks of 14, 10 and 1 uppercase letters respectively.
* 'SA' in positions 9 and 10 of the second block signifies that this is a key for a Standard ('S') Inchi, generated using version 1 ('A') of the InChI software
Thus, for example, the following string is a valid Standard InChiKey in UniChem:
* LFQSCWFLJHTTHZ-UHFFFAOYSA-N
#### **Web Interface Queries**
* Enter plain text only into the query field.
* New-lines and/or white space may be used to separate entries.
* Remove all other non-printing special characters.
* Note that querying with src\_compound\_ids requires additional information:
* The src\_id for the source of the src\_compound\_id's.
* An indication of whether query src\_compound\_ids with 'obsolete' assignments should be included in the query (go [here](https://www.ebi.ac.uk/unichem/info/obsoleteIncExplain) for a more detailed explanation of this option).
* It is recommended that normally users will probably NOT wish to have this option ticked.
* Note, also, that for large queries the output may difficult to interpret, and slow to load in your browser. For larger queries, therefore, users are strongly advised to use the [web services](https://www.ebi.ac.uk/unichem/info/webservices) instead.\
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# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://chembl.gitbook.io/unichem/web-application/formatting-of-input-data-for-unichem-queries..md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.