# Tag Info

13

This sounds like you were exploring work at least related to the work by the Lilienfeld group equally hosting a dedicated site here about data sets already used in their earlier and ongoing exploration of chemical space, programs used to work with the data, and publications. To go considerably higher in molecule count than QM9, you could either go for GDB-...

9

Such values for various properties of liquid water and steam can be looked up in so-called steam tables. Software versions also allow calculations (ususally interpolation) of additional values. For example, I usually use REFPROP – NIST Standard Reference Database (however, not always the latest version) or some old and simple proprietary steam table software ...

9

The ISOL24 database (http://www.thch.uni-bonn.de/tc.old/downloads/GMTKN/GMTKN55/ISOL24.html) contains molecules with up to 81 atoms! The other answer says that there's a database called "OE" with molecules that have up to 174 atoms, but it is "not yet publicly available".

7

I am aware of this range diagram about $\ce{^{81}Br}$ that appeared in the recurrent (open access) IUPAC recommendations of atomic weights in Pure and Applied Chemistry: (source: doi 10.1351/PAC-REP-13-03-02) which cites data of a publication in Environmental Chemistry extending a little to $\ce{^{37}Cl}$ (doi 10.1071/EN10090, open access), too. Even if ...

5

CIF contains coordinates for the atoms in asymmetric unit only (what Ivan called "the independent part" in the comments), plus the set of symmetry operation to fill the remaining space with those atoms. What you want to do is to open CIF in any viewer supporting that format, make sure the unit cell is packed, e.g. the symmetry operations are applied along ...

5

According to the Franck-Condon principle which you are implicitly referring to, absorption is indeed very fast compared to all other processes. If you are looking for time scales of photophysical processes, I can suggest you for example B. Valeur's book "Molecular Fluorescence: Principles and Applications", chapter 3 (Characteristics of fluorescence ...

5

In the current form the question is addressed, and assuming you took a look at a listing of software already in the field like here, I speculate the sheer number of organic reactions (just some) alone renders such a task as a one-man / one-woman project too large. There is a lot of work associated to create such a database, or software. Organic Synthesis is ...

5

Reference 1 reports the isomerization barrier for N‐methylacetohydroxamic acid. From the abstract: We have now determined the activation barrier to C–N rotation from major to minor conformation of a small secondary HA in $\ce{D2O}$ to be 67.3 kJ/mol. The HA rotational barrier scales with solvent polarity, as is observed in amides, although the HA barrier ...

3

Chemical nomenclature is officially defined by IUPAC (International Union of Pure and Applied Chemistry). You can find most IUPAC names for these terpenic compounds by searching their popular names on Wikipedia, they are quite long and confusing terms though, and can only be interpreted if you have a certain knowledge in organic/inorganic chemistry. What ...

3

Until 2005 or 2006 the best source was Chemical Market Reporter. It had the form of a newspaper and was edited once a week. The last pages listed market prices for commodities, some speciality chemicals and also agricultural products. Hundreds of products were listed and you had some idea of what were the options you had for designing an industrial ...

3

I never ran into uv absorption data for (aqueous) sulfuric acid and I doubt that there is any absorption at $\lambda$ = 508 nm. There is an old paper by K. F. Palmer and D. Williams in Appl. Optics, 1975,14, 208-219 (DOI) on the optical properties of sulfuric acid droplets with respects to the composition of clouds on Venus and a more recent one from the ...

3

According to Xemistry, PubChem uses Cactvs for 2D layout coordinate computation. A friend pointed this out to me. If you scroll to the bottom of the CACTVS Toolkit FAQ (http://www.xemistry.com/docs.htm), it says the following: Interesting. I did not know that PubChem is built with Cactvs. I heard it was implemented with OpenEye's OEChem library. ...

3

One resource you can use is the Crystallography Open Database. Search for structures with two elements O and H, and named “ice”. You will then find several experimental structures for cubic ice: with downloadable structure files in CIF format: 1, 2. These were done from X-ray diffraction studies and only feature heavy atoms (oxygen) positions. Although I ...

3

I completely agree with @porphyrin comment. This is an example of crystal data which formatting does not entirely meet IUCr requirements, that's all. This happens a lot, and in most cases it's no big deal. This particular set of coordinates is just not uniform within a single cell. Different crystallographic software uses different means to "reassemble" ...

3

After looking through the sources from the gratefully acknowledged Buttonwood's answer, I also came across CIAAW, which seems to have some of the best available data for the natural isotope abundance ranges of elements like $\ce{C}$, $\ce{H}$, $\ce{N}$, $\ce{O}$, and $\ce{Cl}$. It is based on IUPAC Technical Report 2013 [1]. References Meija, J.; Coplen, T....

3

The usual reference for phase change information, for various substances, is Perry's Chemical Engineers' HandBook by Perry and Green. Then there are the CRC HandBooks and sometimes such information can be gleaned from the Chemical Engineering Encyclopedias (I forget their names now). Then IUPAC, NIST and some other governemntal institutions make such ...

3

The nearest I came to an explanation is an article (Ref. 1) by authors of the database explaining that, in the case of $\ce{H2O (cr,l)}$, the notation (cr,l) refers to the condensed state. Also, a link from the above data page explains that "cr=crystal" and "l=liquid" (thanks MaxW for hinting at the solution). A further update: it finally dawned on me that ...

3

For the Elsevier's Reaxys data base, there is a support page you may consult without subscription, nor log-in to the product. Actually, this is more like a searchable directory, too, because you search for keywords, like «rank», too. Doing so here -- time stamped 25/04/2019 -- offers insight about «How do I view my results?». About half-way through this ...

3

There are several databases of thermochemical properties, a number of them being listed on this Wikipedia page (at the bottom). Most of them are not freely available online, but require subscription. I've searched online but couldn't find that information freely available. Another possible way to get the information would be through a search of the ...

3

Possibly Avogadro may deserve a test complementary to the suggestions by @andselisk, too. Similar as @andselisk, I accessed the 25 degC *.cif data set about Pyrope by Meagher1975 at AMCSD. Already the very first automatic display of the data was the one about an unit cell depicted below: The program may be of interest for you since it allows to save this ...

2

You are absolutely right about suspecting the reliability of sources, based on their value spread. I think, I found what's going on with those internet (I assumed) sources. Yet, I know everybody agree with me that CRC handbook of chemistry and physics is The Bible for Physical Constants of Organic Compounds. Here is what I found on 2005 Internet Version of ...

2

As a side note, "JANAF" stands for Joint Army–Navy–Air Force; these tables were designed to provide quick access to the thermodynamic data for rocket scientists. Here, $Δ_\mathrm{f}H^\circ$ is the standard enthalpy of formation. The difference $H-H^\circ(T_\mathrm{r})$ is required to calculate the standard enthalphy of reaction $Δ_\mathrm{r}H^\circ$ if in ...

2

An elder way would be the via book examples, like «Organic Structures from Spectra» by Field, Sternhell, Kalman, with dozens and dozens of combined exercises in a format like the following: and currently available in the 5th edition by Wiley (e.g., here). There is a related project of «Interactive Spectroscopy Problems» by the University of Calgary (here), ...

2

The NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) is a program that can calculate the thermodynamic and transport properties of some important fluids and their mixtures. It was developed by the National Institute of Standards and Technology (NIST) and is commercially available as NIST Standard Reference Database 23 here. For ...

2

Since you're a Dutch neighbour, the European Chemicals Agency might be an option.

2

I've used base64 encoding in the past for escaping SMILES strings for use as filenames.

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From my experience, the only characters that have been a problem are '/', '\', and '#'. I replace them with 'z', 'x', '^' respectively. It's not a convention but just something I've come up with. If you were to use the file name in a command, '(', ')', '\$' would also need to be escaped.

2

As long as you are not looking for something very specific, and you are not performing a sanity check of what you are matching against, the provided regular expression will match more often wrong than falsely not matching. It will even match more nonsense InChI than total number of existing ones. It is therefore not much better than the trivial catch them ...

2

Beyond other answers, I'd suggest the original PubChemQC project, which offers ~3 million molecules from PubChem optimized using DFT (B3LYP/6-31G*). Molecules include a wide variety of elements as long as the molecular mass is less than 500 Da. (Roughly speaking that should still handle ~38 carbon atoms.) "PubChemQC Project: A Large-Scale First-Principles ...

1

Sigma Aldrich was mentioned, and is a very good source of relative pricing; it can help eliminate certain possibilities when you see compounds listed in 1 gram quantities vs 1 kg or more. Another item is the intended size of purchase and perhaps continued purchases. Prices in bags, pallets (2000 lb.) or pails, drums, totes or truckload (20 tons) will vary ...

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