Imperial College London

Henry Rzepa

[Harnessing FAIR
data](https://www.ses.ac.uk/event/harnessing-fair-data/) is an event
being held in London on September 3rd; no doubt all the speakers will
espouse its virtues and speculate about how to realize its
potential.[^♥^]{style="color: #ff0000;"} Admirable aspirations indeed.
Capturing hearts and minds also needs lots of real life applications!
Whilst assembling a [forthcoming
post](https://www.ch.imperial.ac.uk/rzepa/blog/?p=19828) on this blog, I
realized I might have one nice application which also pushes the
envelope a bit further, in a manner that I describe below.

The post I refer to above is about using quantum chemical calculations
to chart possible mechanistic pathways for the reaction between a
carboxylic acid and an amine to form an amide. The FAIR data for the
entire project is [collected]{style="color: #ff0000;"} at
DOI: [10.14469/hpc/4598](https://data.hpc.imperial.ac.uk/resolve?doi=4598){target="FAIR"}.
Part of what makes it FAIR is the metadata not only collected about this
data but also formally registered with the DataCite agency. Registration
in turn enables [Finding]{style="color: #ff0000;"}; it is this aspect I
want to demonstrate here.

The
[metadata](https://data.datacite.org/application/vnd.datacite.datacite+xml/10.14469/hpc/4598)
for the above DOI includes information such as;

1.  The ORCID persistent identifier (PID) for the creator of the data
    (in this instance myself)
2.  Date stamps for the original creation date and subsequent
    modifications.
3.  A rights declaration, in this case the CC0 license which describes
    how the data can be re-used.
4.  Related identifiers, in this case describing members of this
    [collection]{style="color: #ff0000;"}.

The data itself is held in the members of the collection, each of which
is described by a more specific set of
[metadata](https://data.datacite.org/application/vnd.datacite.datacite+xml/10.14469/hpc/4606)
in addition to the more general types in the above list
(e.g. [10.14469/hpc/4606](https://doi.org/10.14469/hpc/4606)).

5.  One important additional metadata descriptor is the **ORE** locator
    (Object Re-use and Exchange, itself almost a synonym for FAIR). This
    allows a machine to deduce a direct path to the data file itself,
    and hence to retrieve it automatically if desired. It is important
    to note that the DOI itself
    (i.e. [10.14469/hpc/4606](https://doi.org/10.14469/hpc/4606)) points
    only to the "landing page" for the dataset, and does not necessarily
    describe the direct path to any specific file in the dataset. The
    ORE path can be used with *e.g.* software such as JSmol to directly
    load a molecule based only on its DOI. You can see an example of
    this
    [here](http://www.ch.ic.ac.uk/rzepa/talks/amsterdam18/2018-1.html).
6.  Each molecule-based dataset contains additional specific metadata
    relating to the molecule itself. For example this is how the
    InChiKey, an identifier specific to that molecule, is expressed in
    metadata;  
    `<subject subjectScheme="inchikey" schemeURI="http://www.inchi-trust.org/">PVXKWVPAMVWJSQ-UHFFFAOYSA-N</subject>`  
    The advantage of expressing the metadata in this way is that a
    general search of the type:  
    [`https://search.datacite.org/works?query=subjexts.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N`](https://search.datacite.org/works?query=subjects.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N){target="_blank"
    rel="noopener"}  
    can be used to track down any molecule with metadata corresponding
    to the above InChIkey.
7.  Here is more metadata, introduced in this blog. It relates to the
    (computed) value of the Gibbs energy (the energy unit is in
    Hartree^†^), as returned by the Gaussian program;  
    `<subject subjectScheme="Gibbs_Energy" schemeURI="https://goldbook.iupac.org/html/G/G02629.html" valueURI="http://gaussian.com/thermo/">-649.732417</subject>`  
    I here argue that it represents a unique identifier for a molecule
    calculation using the quantum mechanical procedures implemented in
    *e.g.* Gaussian. This identifier is different from the InChIkey, in
    that it can be truncated to provide different levels of information.
    - At the coarsest level, a search of the type  
      [`https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*`](https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*)  
      should reveal all molecules with the same number of atoms and
      electrons whose Gibbs energy has been calculated, but not
      necessarily with the same InChI (*i.e.* they may be isomers, or
      transition states, etc). This level might be useful for revealing
      most (not necessarily all^‡^) molecules involved in say a reaction
      mechanism. It should also be insensitive to the program system
      used, since most quantum codes will return a value for the Gibbs
      energy if the same procedures have been used (*i.e.* DFT method,
      basis set, solvation model and dispersion correction) accurate to
      probably 0.01 Hartree.
    - The top level of precision however is high enough to almost
      certainly relate to a specific molecule and probably using a
      specific program;  
      [`https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.732417`](https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.732417)
    - The searcher can experiment with different levels of precision to
      narrow or broaden the search.
    - I would also address the issue (before someone asks) of why I have
      used the Gibbs energy rather than the Total energy. Put
      simply, the Gibbs energy is far more useful in a chemical context.
      It can be used to relate the relative Gibbs energies of different
      isomers of the same molecule to *e.g.* the equilibrium constant
      that might be measured. Or the difference in Gibbs energies
      between a reactant and a transition state can be used to derive
      the free energy activation barrier for a reaction. The total
      energy is not so useful in such contexts, although of course it
      too could be added as a subject in the metadata above if a real
      use for it is found.
8.  The searcher can also use Boolean combinations of metadata, such as
    specifying both the InChIKey and the Gibbs Energy, along with say
    the ORCID of the person who may have published the data;  
    [`https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*+AND+ subjects.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N+AND+contributors.nameIdentifiers.nameIdentifier:*0000-0002-8635-8390`](https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*+AND+subjects.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N+AND+contributors.nameIdentifiers.nameIdentifier:*0000-0002-8635-8390){target="_blank"
    rel="noopener"}^♥^

I have tried to show above how FAIR data implies some form of rich
(registered) metadata. And how the metadata can be used to Find (the F
in FAIR) data with very specific properties, thus [Harnessing FAIR
data]{style="color: #0000ff;"}.

------------------------------------------------------------------------

^†^It is a current limitation of the V4.1 DataCite schema that there
appears no way to specify the data type of the subject, including any
units.

^‡^In theory, a [range query](http://yonik.com/solr/query-syntax/) of
the type:  
[`https://search.datacite.org/works?query=subjects.subjectScheme:Gibbs_energy+AND+subjects.subject:[\-649.1 TO \-649.8]`]{.small}
should be more specific, but I have not yet gotten it to work, probably
because of the lack of data-typing means it is not recognised as a range
of numeric values.

^♥^Implicit in this search is the grouping  
[`https://search.datacite.org/works?query=(subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*) + (subjects.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N)+AND+contributors.nameIdentifiers.nameIdentifier:*0000-0002-8635-8390`](https://search.datacite.org/works?query=(subjects.subjectScheme:Gibbs_Energy+AND+subjects.subject:\-649.*)+AND+(subjects.subjectScheme:inchikey+AND+subjects.subject:CZABGBRSHXZJCF-UHFFFAOYSA-N)+AND+contributors.nameIdentifiers.nameIdentifier:*0000-0002-8635-8390%0A)  
Currently however DataCite do not correctly honour this form of
grouping.

[^♥^]{style="color: #ff0000;"}[Video of the speakers and the panel
session](http://www.ses.ac.uk/2018/10/04/fair/#tab-panel-session){target="_blank"
rel="noopener"} at the end is now available.

::: {.wp_orcid_field}
[https://orcid.org/0000-0002-8635-8390](https://orcid.org/0000-0002-8635-8390){target="_blank"
rel="author"}
:::


Harnessing FAIR data is an event being held in London on September 3rd; no doubt all the speakers will espouse its virtues and speculate about how to realize its potential.
<sup>
 ♥
</sup>
Admirable aspirations indeed. Capturing hearts and minds also needs lots of real life applications!

Harnessing FAIR data:  A suggested useful persistent identifier  (PID) for quantum chemical calculations.

Almost exactly 20 years ago, I started what can be regarded as the
precursor to this blog. As part of a celebration of this
anniversary,\[cite\]10.3390/molecules22040549\[/cite\] I revisited the
page to see whether any of it had withstood the test of time. Here I
recount what I discovered.

The site itself is at
[www.ch.ic.ac.uk/motm/perkin.html](http://www.ch.ic.ac.uk/motm/perkin.html) 
and has the title "*Mauveine: The First Industrial Organic
Fine-Chemical*" It was an application of an earlier
experiment\[cite\]10.1039/P29950000007\[/cite\] to which we gave the
title "*Hyperactive Molecules and the World-Wide-Web Information
System*". The term *hyperactive* was supposed to be a play on
hyperlinking to the active 3D models of molecules built using their 3D
coordinates. The word has another, more negative, association with food
additives such as tartrazine -- which can induce hyperactivity in
children -- and we soon discontinued the association. This page was cast
as a story about a molecule local to me in two contexts; the first being
that the discoverer of mauveine, W. H. Perkin, had been a student at
what is now the chemistry department at Imperial College. The second was
the realization that where we lived in west London was just down the
road from [Perkin's manufacturing
factory](http://www.ch.imperial.ac.uk/rzepa/blog/?p=9754){target="_blank"}.
Armed with (one of the first) digital cameras, a Kodak DC25, I took some
pictures of the location and added them later to the web page. The page
also included two sets of 3D coordinates for mauveine itself and
alizarin, another dyestuff associated with the factory. These were
"activated" using HTML to make use of the then very new [Chime browser
plugin](https://en.wikipedia.org/wiki/MDL_Chime){target="_blank"}; hence
the term *hyperactive molecule*.

This first effort, written in December 1995, soon needed revision in
several ways. I note that I had maintained the site in 1998, 2001, 2004
and 2006. This took the form of three postscripts to add further
chemical context and more recent developments and in replacing the
original Chime code for Java code to support the new Jmol software
(Chime itself had been discontinued, probably around 2001 or possibly
2004). With the passage of a further ten years, I now noticed that the
hyperactive molecules were no longer working; the original Jmol applet
was no longer considered secure by modern browsers and hence
deactivated. So I replaced this old code with the [latest
version](https://sourceforge.net/projects/jmol/files/){target="_blank"}
(14.7.5 as **JmolAppletSigned.jar**) and this simple fix has restored
the functionality. The coordinates themselves were invoked using the
HTML applet tag, which amazingly still works (the applet tag had
replaced an earlier one, which I think might have been embed?).  A
modern invocation would be by using *e.g.* the JSmol Javascript based
tool and so perhaps at some stage this code will indeed need
further revision when the Java-based applet is permanently disabled.

![](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/038-1024x419.jpg){.aligncenter
.size-large .wp-image-17391 loading="lazy" decoding="async" width="450"
height="184"
srcset="https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/038-1024x419.jpg 1024w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/038-300x123.jpg 300w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/038-768x314.jpg 768w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/038.jpg 1618w"
sizes="(max-width: 450px) 100vw, 450px"}

You may also notice that the 3D coordinates are obtained from an XML
document, where they are encoded using CML (chemical markup
language\[cite\]10.1021/ci990052b\[/cite\]), which is another expression
from the family that HTML itself comes from. That form may well last
rather longer than earlier formats -- still commonly used now -- such as
.pdb or .mol (for an MDL molfile). 

Less successful was the attempt to include buttons which could be used
to annotate the structures with highlights. These buttons no longer work
and will have to be entirely replaced in the future at some stage.

![](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/039-1024x152.jpg){.aligncenter
.size-large .wp-image-17392 loading="lazy" decoding="async" width="450"
height="67"
srcset="https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/039-1024x152.jpg 1024w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/039-300x45.jpg 300w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/039-768x114.jpg 768w, https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2017/02/039.jpg 1844w"
sizes="(max-width: 450px) 100vw, 450px"}

The final part of the maintenance (which I had probably also done with
the earlier versions) was to re-validate the HTML code. Checking that a
web page has valid HTML was always a behind-the-scenes activity which I
remember doing when constructing the [ECTOC
conferences](http://www.ch.ic.ac.uk/ectoc/) also back in 1995 and doing
so probably does prolong the longevity of a web page. This requires
"tools-of-the-trade" and I use now (and indeed did also back in 1995 or
so) an industrial strength HTML editor called BBedit. To this is added
an HTML validation tool, the installation of which is described
at <https://wiki.ch.ic.ac.uk/wiki/index.php?title=It:html5> I re-ran
this again^†^ and so this 2017 version should be valid for a little
while longer at least. The page itself now has not just a URL but a
[persistent
version](https://en.wikipedia.org/wiki/Persistent_identifier){target="_blank"}
called a DOI (digital object identifier), which
is [10.14469/hpc/2133](https://doi.org/10.14469/hpc/2133)\[cite\]10.14469/hpc/2133\[/cite\].
In theory at least, even if the web server hosting the page itself
becomes defunct, the page could -- if moved -- be found simply from its
DOI. The present URL-based hyperlink of course is tied to the server and
would not work if the server stopped serving.

To complete this revisitation, I can add here a recent result^‡^. Back
in 1995, I had obtained the 3D coordinates of mauveine using molecular
modelling software (MOPAC) together with a 2D structure drawing package
(ChemDraw) because no crystal structure was available. Well, in 2015
such structures were finally
published.\[cite\]10.3184/174751915X14474318419130\[/cite\] Twenty years
on from the original "hyperactive" models, their crystal structures can
be obtained from their assigned DOI, much in the same manner as is done
for journal articles: Try
DOI: [10.5517/CC1JLGK4](http://doi.org/10.5517/CC1JLGL5){target="CCDC"}\[cite\]10.5517/CC1JLGK4\[/cite\]
or
DOI: [10.5517/CC1JLGL5](http://doi.org/10.5517/CC1JLGL5){target="CCDC"}\[cite\]10.5517/CC1JLGL5\[/cite\].

At some stage, ***web archaeology*** might become a fashionable pursuit.
Twenty year old Web pages are actually not [that
common](http://www.ch.imperial.ac.uk/rzepa/blog/?p=14448){target="_blank"}
and it would be of interest to chart their gradual decay as security
becomes more important and standards evolve and mature. One might hope
that at the age of 100, they could still be readable (or certainly
rescuable). During this period, the technology used to display 3D models
within a web page has certainly changed considerably and may well still
do so in the future. Perhaps I will revisit this page in 2037 to see how
things have changed!

------------------------------------------------------------------------

^†^The old code can still be seen
at www.ch.ic.ac.uk/motm/perkin-old.html

^‡^It should really be postscript 4.

::: {.wp_orcid_field}
[https://orcid.org/0000-0002-8635-8390](https://orcid.org/0000-0002-8635-8390){target="_blank"
rel="author"}
:::


Almost exactly 20 years ago, I started what can be regarded as the precursor to this blog. As part of a celebration of this anniversary,[cite]10.3390/molecules22040549[/cite] I revisited the page to see whether any of it had withstood the test of time. Here I recount what I discovered. The site itself is at www.ch.ic.ac.uk/motm/perkin.html

Revisiting (and maintaining) a twenty year old web page. Mauveine: The First Industrial Organic Fine-Chemical.

Scientists are familiar with the term [data,]{style="color: #0000ff;"}
at least in a scientific or chemical context, but appreciating
[metadata]{style="color: #0000ff;"} (meaning \"after\", or \"beyond\")
is slightly more subtle, in the sense of using it to mean data about
data. The challenge lies in clarifying where the boundary between data
and its metadata lies and in specifying and controlling the vocabulary
used for these metadata descriptions. Items in a chemical metadata
dictionary might include *e.g.* subject classifications such as *Organic
Molecular Chemistry* or identifiers such as *InChIkey*. But what could
[metametadata ]{style="color: #0000ff;"}be? Here I briefly show some
examples by way of illustration.

Let me start by defining a data repository as a store of both data
**and** the metadata describing it. The metadata is to be exposed in a
standard manner which allows it to be aggregated by other agencies.
Nowdays, it is becoming common to identify such a data object together
with its metadata using a persistent identifier, or DOI. But to decide
if any particular repository and the data objects contained therein is
generally useful to you, you need information about the metadata itself.
Technically, this is defined using a
**schema**\[cite\]10.2312/re3.008\[/cite\] describing the metadata
(which might *e.g.* identify any dictionaries used); hence
[metametadata]{style="color: #0000ff;"}. Now you need to store the
metametadata and so I introduce the concept of a registry which does
this. This metametadata object is itself assigned a DOI^‡^ and here I
list these DOIs for a personal selection of some chemically oriented
examples, in this case deriving from the largest registry of research
data repositories [**re3data.org.** ]{style="color: #0000ff;"}You can
search for your own entry at their site:
[http://service.re3data.org/search](http://service.re3data.org/search){target="_blank"}.

|                                                                        |                                                                                                                                      |                                                                                                                                                            |
|------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Data repository                                                        | The repository metametadata DOI^♣^                                                                                                   | Badge                                                                                                                                                      |
| Figshare                                                               | [10.17616/R3PK5R](http://doi.org/10.17616/R3PK5R){target="_blank"}\[cite\]10.17616/R3PK5R\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010066.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Zenodo                                                                 | [10.17616/R3QP53](http://doi.org/10.17616/R3QP53){target="_blank"}\[cite\]10.17616/R3QP53\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010468.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Cambridge structure database                                           | [10.17616/R36011](http://doi.org/10.17616/R36011){target="_blank"}\[cite\]10.17616/R36011\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010197.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Crystallographic open database                                         | [10.17616/R37S31](http://doi.org/10.17616/R37S31){target="_blank"}\[cite\]10.17616/R37S31\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010213.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Oxford University Research Archive                                     | [10.17616/R3Q056](http://doi.org/10.17616/R3Q056){target="_blank"}\[cite\]10.17616/R3Q056\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100011230.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Open Notebook Science                                                  | [10.17616/R3859D](http://doi.org/10.17616/R3859D){target="_blank"}\[cite\]10.17616/R3859D\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010113.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Usefulchem                                                             | [10.17616/R3Z89N](http://doi.org/10.17616/R3Z89N){target="_blank"}\[cite\]10.17616/R3Z89N\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010680.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Chemotion                                                              | [10.17616/R34P5T](http://doi.org/10.17616/R34P5T){target="_blank"}\[cite\]10.17616/R34P5T\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010748.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Chemspider                                                             | [10.17616/R38P4P](http://doi.org/10.17616/R38P4P){target="_blank"}\[cite\]10.17616/R38P4P\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010205.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Chemical Database Service                                              | [10.17616/R36P42](http://doi.org/10.17616/R36P42){target="_blank"}\[cite\]10.17616/R36P42\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100000021.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Imperial College HPC data repository.                                  | [10.17616/R3K64N](http://doi.org/10.17616/R3K64N){target="_blank"}\[cite\]10.17616/R3K64N\[/cite\],\[cite\]10.14469/hpc/382\[/cite\] | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100011965.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |
| Imperial College SPECTRa repository.\[cite\]10.1021/ci7004737\[/cite\] | [10.17616/R30316](http://doi.org/10.17616/R30316){target="_blank"}\[cite\]10.17616/R30316\[/cite\]                                   | ![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/100010719.svg){.aligncenter .size-full .wp-image-15936 decoding="async" width="200"} |

Not all of the repositories listed in the table above assign formal DOIs
to their data collections, meaning that the metadata for their entries
cannot be aggregated in a searchable manner using *e.g.*
[search.datacite.org/ui](http://search.datacite.org/ui){target="_blank"}
(or [search.datacite.org/api](http://search.datacite.org/api) for the
machine version). Currently, the metametadata does not fully carry this
information, an aspect which I gather will be rectified in a future
revision of the re3data schema.\[cite\]10.2312/re3.008\[/cite\]

Importantly, both metadata and (repository) metametadata can be searched
using [API](http://service.re3data.org/api/doc){target="_blank"}s
(application programmer interface), ensuring that the entire flow of
meta information can be subject to automated software analysis rather
than just visual inspections by a human.This should allow a rich and
[**open**]{style="color: #0000ff;"} infrastructure for handling research
objects or data to be built up using hierarchical metadata. The examples
above indeed show that the chemical space is already the largest
component of the Natural Sciences space.

[![NH3-8](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/269.jpg){.aligncenter
.size-full .wp-image-15936 decoding="async"
width="450"}](http://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2016/04/269.jpg){target="_blank"}

Although the edifice is still largely in its infancy, already I think we
can start to see an alternative open approach emerging to \"Googling\"
for data, or the even older traditional bespoke (*i.e.* non-open)
services offered by commercial human-based abstractors of chemical
metadata.

------------------------------------------------------------------------

^‡^This DOI is information about the metametadata, and hence it is
metametametadata, or **m3data**. Sorry! ^♣^The citations at the foot of
this post are generated entirely automatically (by a WordPress plugin
called Kcite) from the m3data associated with each entry, *i.e.* the DOI
listed. Were the persistent identifier for the entry ever to be changed,
this would propagate automatically to the citation, unlike the static
entries in the table.

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Scientists are familiar with the term data, at least in a scientific or chemical context, but appreciating metadata (meaning "after", or "beyond") is slightly more subtle, in the sense of using it to mean data about data. The challenge lies in clarifying where the boundary between data and its metadata lies and in specifying and controlling the vocabulary used for these metadata descriptions.

Messaggi di Rogue Scholar

Harnessing FAIR data: A suggested useful persistent identifier (PID) for quantum chemical calculations.

Revisiting (and maintaining) a twenty year old web page. Mauveine: The First Industrial Organic Fine-Chemical.

Metametadata: data about data about (chemical) data.