Rituraj Kalita

The Internet offers an unbelievably huge and largely systematic collection of chemical information and other chemical resources, a large and significant part of which is free for anyone. However, accessing it properly requires some knowledge on the part of the user. We may classify the web-available chemical resources into the following types: (i) background conceptual knowledge, generally of the undergraduate and master's degree level (ii) Papers in journals & seminar-proceedings describing original research work (iii) web-databases specifying and describing specific molecules & macromolecules (iv) software-packages such as ORTEP, Protein Explorer, RasMol, ArgusLab or GAMESS etc. that helps in visualization, drawing, computation or even virtual experimentation in chemistry.

The background knowledge (similar to chemistry textbooks) web-storehouse in chemistry is mostly free and is already quite huge, yet it is growing fast. This is because of contributions from individual authors and via the philanthropic initiatives of web-encyclopedias (e.g, encyclopedia.com, en.wikipedia.org, britannica.com), science-organizations (e.g., scienceworld.wolfram.com/chemistry) & university departments (e.g., chem.ox.ac.uk, science.uwaterloo.ca, wou.edu). To search for  knowledge of a chemistry topic such as ionic solids, chlorofluorocarbons or liquid crystals, one may enter into one of these websites (may see examples for wikipedia and wolfram main-page). After logging in, one comes across its opening screen with a space to type in the required topic to search for (in the above two examples, note respectively the words liquid crystals and ionic solids, typed by the user). After entering a topic (such as any one of the above), several links to several articles (see a wikipedia example), each article ranging from half a page to a few pages are shown, the first one of which is generally the most relevant (see the nice wikipedia example). Special mention must be made about the book-storing initiative (books.google.com) by Google, which initiative is making available even pages from the printed priced books anywhere in the world, free of cost to anyone interested. An alternative way of locating such knowledge is to enter a free Search Engine, the best of which includes google.com, altavista.com and yahoo.com , and similarly search for the topic therein (see an example). This would, however, lead to links about information (see an informative example with some unbelievably clear pictures)  almost everywhere from the Internet (as an example, even this author's online chemistry materials may be so tracked). After entering the required topic in the form of liquid+crystals or organic+reaction+mechanism etc. (the plus sign between two words ensures the existence of both words in the found sites), one comes across several, sometimes too many, links to sites of organizations, universities or individuals that deal with the required topics, in elementary ways or in advanced ways (see an example originating from Oxford University, UK).

Coming to scholarly chemistry journals and proceedings, one may locate sites of different chemistry journals by searching for chemistry+journal in any good search engine. Of highest relevance are the sites rsc.org/Publishing/Journals and  pubs.acs.org/journals, leading to the multitude of very good chemistry journals published respectively by the Royal Society of Chemistry (Europe) and the American Chemical Society (USA). One may even search for keywords in the title/abstract (e.g. potential+energy+dimer) or author (e.g. Timothy+Young) of papers in these journals, by entering the words in the space provided for advanced searching within title name, abstract or author names (see the RSC example: Step-1 & Step-2). To search within most of the important journals in the world in one go, the best way is, however, to enter into a science-specific, academic-specific or chemistry-specific search engine (in contrast to general search engines which do not locate journals and proceedings) such as scirus.com (see example), scholar.google.com (see example), sciencedirect.com (see example) or chemweb.com. Everywhere, the advanced search options are generally more helpful (see the scirus.com example), and sometimes one might need (as in the case of chemweb.com) to become a member, mostly free of cost, to search in some of these search engines. A characteristic feature of these sites (e.g., scirus.com for science-search) is the free availability of even the abstracts, in addition to the titles, author-names, journal-issues etc. To carry home a rich harvest of abstracts to your off-line home/institutional computer, a good idea is to select, copy (see example) and then paste (see example) the abstracts one by one into a suitably-named WordPad/ Word file, and then finally to save that WordPad/ Word file and bring that file home within a CD (compact disk)/ pen-drive. In some cases, you could also come across some full-papers being distributed free of cost. After getting name of an author of two or more papers in a subject, a good idea is to search for other papers written by that author, by entering his/her name as a keyword (see example). [This helps in locating papers that actually dealt with the subject mentioned in the keywords, but does not explicitly contain the keywords in the title/abstract of the paper.]

There are web-databases, mostly free, that systematically stores the (common & chemical) names, structures, properties and reactions etc. of chemical molecules (i.e., substances). Foremost among them are CrossFire Beilstein (website beilstein.com), PubChem (website pubchem.ncbi.nlm.nih.gov) at NCBI (USA), and NIST (USA) Chemistry WebBook (webbook.nist.gov/chemistry). Click here to see an image of the NIST homepage, within which you may click at the hyperlink Name to access an name-wise search window, where you may feed in the name (say 2-nitro toluene) to get a lot of chemical data about the substance, as shown here and also here. For macromolecules of biological origin, including proteins, nucleic acids, carbohydrates etc., there are the Protein Data Banks (PDB-s) which store and freely disseminate the 3-D structural and other relevant data of such macromolecules. The original three such data-banks in USA (called RCSB PDB, website rcsb.org/pdb), Europe (called MSD EBI, website www.ebi.ac.uk/msd) and Japan (called PDBj, website pdbj.org) are presently collaborating to form a single, combined store of bio-macromolecular data, known as Worldwide Protein Data Bank (in wwpdb.org, see image). Both of these classes (chemical and bio-chemical) of web-databases may be searched by using common names, chemical names, relevant keywords (say the keywords human serum albumin) or codes of the molecule/ macromolecule (every known macromolecule is given a characteristic 4-letter code called the  PDB  ID).  See example-steps 01 and 02 about searching the RCSB PDB database, you may then click at a button with the appearance () corresponding to a search-result item to download the descriptive, structure-describing PDB-file (see example) for the corresponding macromolecule. As shown here, the PDB-file (thus downloaded and saved) may be opened with ORTEP / ArgusLab / Protein Explorer / RasMol so as to view the macromolecular structure.

The chemistry-centered software-packages mentioned earlier could be generally obtained free of cost from the individual or institutional website of the developer scientists. Molecular or macromolecular structures obtained from the web-databases (mentioned in the last paragraph) will be hardly meaningful if a structure-visualization package such as ORTEP-3 (website chem.gla.ac.uk/~louis/software/ortep3) or Protein Explorer (umass.edu/microbio/chime/explorer) is lacking. Any chemistry educator or student should also be armed with a 3-D molecular model-making package say ArgusLab (website planaria-software.com), a molecule & reaction drawing package say ISIS/Draw (mdli.com), and a computational chemistry package say PC-GAMESS (classic.chem.msu.su/gran/gamess). All these resources could be simply downloaded from the respective website (as mentioned here; see the ArgusLab example) free of cost and then easily installed (see a crucial step within the ArgusLab installation). For ISIS/Draw, as shown here, the help-files need to be separately installed.

To complete the discussion, here mention should also be made of the virtual chemical experimentation packages available from the web, including even a virtual NMR spectrophotometer!