chemicals

[xenogen]

how many chemicals identified in the world

[theprof]

Hmm, sorry RoaldoM, but your answer is debatable.

I've been a user of CAS registry for many years and my university laboratories have added the odd substance or two to the list over that time. At times, we work with such horrendously long named chemicals, that we prefer to refer to them by their CAS number. The figure you've given is the latest "CAS Registry Number and Substance Count" which you've probably sourced from here:

http://www.cas.org/cgi-bin/cas/regreport.pl

Now that figure is not what it seems at first glance despite the fact that it says it is a count of "organic and inorganic substances"

The figure actually includes not only those two categories of chemical substances but also metals, alloys, elements, polymers, isomers, organometallic substances, minerals and a host of other substances including biological sequences. Tin for example is 7440-31-5, red Phosphorus is 29879-37-6 and Wood's Metal 8049-22-7

(continued)

[theprof]

Now before I would have answered the question, I would have had to ask xenogen to explain what he meant in more detail..

For example, if he meant the number of substances that have been isolated or manufactured and sit in glass jars on laboratory shelving, the figure is a fraction of that 34 million figure.

In addition, you can't really include alloys as they they may be defined as materials having metallic properties and composed of two or more intimately mixed chemical elements, of which at least one is a metal. In this case the CAS list contains the CAS number of the individual elements plus the CAS number of the alloy. Alloys alone therefore inflate the CAS list massively.

I also think that because the question is fairly simple, xenogen didn't really have polymers in mind, and again huge numbers of them are now known, all of which are contained in that 34,371,954 figure. The same probably applies to amino-acids and other biochemical substances.

A "chemical" may be defined as any substance characterised by a definite molecular composition and therefore the CAS list quite rightly lists all such substances. However did xenogen really have alloys and suchlike in mind when asking the question?

[EDLEE]

Prof,
I doubt that xenogen has much interest in your answer, as it would entail the effort of reading more than one line.

I base this, both , on the length and wording of the question and on the several similar questions posed within three minutes.

While I always enjoy reading your reasoned and well thought out answers, I feel it does a disservice to the educational institutions for you to give them to those who should be, as part of their learning process, finding them on their own.

I hope that I haven't offended anyone,,xenogen excepted,, and that you will remain a resource for those that deserve it.
ed

[theprof]

EDLEE,

Thanks for that. I appreciate the point you make and you are undoubtedly correct in your assessment of the very simplistic questions submitted by xenogen.

I was aware that my answer would go over he top of the head of xenogen, but that was not the purpose of my post. The answer I provided was intended to show to RoaldoM that the information he/she had gleaned from the CAS website was not to to be taken too factually for the reasons I outlined. RoaldoM is to be admired as he/she has done his/her best to provide a succinct answer to the question submitted, but due to the complexity of the CAS registration system has unfortunately been misled. This page may clarify the situation:

http://www.cas.org/expertise/cascontent/regist ry/regsys.html

I, like many of my learned colleagues who post on AB, am all too well aware of the benefits of learning how to research a topic and I always try to be conscious that one of my answers may be copied down verbatim by an indolent student be that person at school or college. Most of the time, I like to think I get it right. However, nothing in my two posts above was directly of use to xenogen - I merely pointed out to RoaldoM that all was not what it seemed.

Had I given xenogen a different figure and stated why it was better than the one provided by RoaldM, that would have been a different story. The reality is that the best scientific brains in the world could not give xenogen the definite figure he or she sought because it's constantly increasing.

(continued)

[theprof]

Nevertheless, I must admit that I do have some sympathy with students who are at university and are having problems with advanced chemistry or biochemistry, This is why I provided a fairly good outline answer on the 15.03.08 regarding phosphoglucomutase, for which there is a dearth of useful information around, but which hopefully, would have sent the student off to research further. The important thing here is that that students who are trying their best and post on AB stand out a mile in comparison to the simplistic, vague questions posed by xenogen et al.

Finally, don't think for a moment that you've offended me. I really do appreciate constructive criticism about my answers and you've made very valid points. I'm very grateful. Finally, Thanks for your appreciation of answers - I try my best!

[xud]

Poor old xenogen, I bet he wishes he hadn't asked the question now.

[Frederick16]

There are 800000+ chemicals found in the world.
http://www.reddynreddypharma.com/speciality-chemicals-manufacturers-india.php

[Frederick16]

There are 800000+ chemicals found in the world.

chemicals