Questions tagged [databases]

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12
votes
3answers
827 views

What are datasets containing molecules with more than 38 heavy atoms?

I have been testing a machine learning approach for molecular energy prediction. The current dataset that I have is QM9, which is consist of molecules with up to 9 heavy atoms. I was wondering if ...
0
votes
0answers
22 views

Do any decent thermochemical databases exist? [duplicate]

The more thermochemical properties the better, but specific heat/ specific heat capacity is what I am looking for.
1
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1answer
57 views

What is the meaning of the phase state label (cr,l) appearing in ATcT thermochemical data tables?

I was examining data associated with this post on the heat of solution of ammonium nitrate when I came upon the NIST ATcT data page which lists the heat of formation of $\ce{(NH4)NO3(cr,l)}$. In this ...
3
votes
1answer
109 views

Where can I find example MS, IR, NMR spectra for teaching molecular spectroscopy?

I am teaching a course on analytical chemistry, and I would like to give my students MS, IR and NMR spectra to practice with. It would be ideal if they could analyze spectra in a more "realistic" way ...
9
votes
1answer
52 views

What does “reaction rank” in Reaxys stand for?

By exporting some search results from Reaxys, I found "Reaction rank" to be one of the columns in the Excel file. In my file, values descend from 107 to 52 and skip some values in-between too. Does ...
2
votes
1answer
33 views

Is there any book where specific heat capacities are given?

I want to find the value of the specific heat capacity of aluminium nitrate nonahydrate, in order to calculate mixing effects in a chemical reaction. I am looking for a source, such as a book or link ...
2
votes
2answers
600 views

How can I get xyz coordinates of atoms of a unit cell structure from CIF format files?

I'm trying to run DFT or other 1st principle simulation of Pyrope ($\ce{Mg3Al2Si3O12)}$ and Grossular $\ce{(Ca3Al2[SiO4]3)}$ unit cell structure. So, I'm looking for unit cell xyz periodic box ...
6
votes
2answers
397 views

What is a good source for large tables on the properties of water?

I'm currently doing an investigation for school on finding the Clausius-Clapeyron relation/gradient for boiling water and comparing it to the gradients along my line of best fit. It is given by the ...
0
votes
0answers
58 views

Looking for experimental data for titration curves

I am looking for real, open source and free experimental dataset (not image, scan of table) of acid/base titration curves: pH versus titrant volume for many combination (strong/weak acid/base, ...
0
votes
1answer
198 views

Where can I find reliable data for melting points of organic compounds?

I'm interested in the melting/freezing points of organic compounds, but the online literature has data that's all over the map. I can understand that especially for isomers of alkanes, pure samples ...
0
votes
1answer
73 views

What is the difference between ΔfH and H-H° in NIST–JANAF tables?

Can someone explain the difference between $Δ_\mathrm{f}H$ and $H-H^\circ$ in NIST–JANAF tables?
5
votes
2answers
61 views

Where can I find ranges of isotope abundances?

I'd like to know how much stable isotopes like $\ce{^{13}C}$, $\ce{^2H}$, $\ce{^{17}O}$ and $\ce{^{18}O}$ deviate from their natural abundances in the earth's crust among all possible compounds we may ...
1
vote
0answers
31 views

Online list of water of crystallisation?

I was extremely happy to recently receive a copy of the Nuffield Revised Book of Data but was somewhat disappointed to find that it did not list data on the water of crystallisation for various ...
2
votes
0answers
120 views

Spectral database in the UV-Vis/NIR and IR regime

I'm searching for a bunch of spectra (some tens), preferably with intense bands in the Vis spectrum, to play around with (calculating chromaticity, etc.). They should range from 250 nm to 2500 nm (UV-...
5
votes
0answers
179 views

Pseudo 3D skeletal structure style which emphasizes geometry

If one searches and navigates to a wiki page for, say, dichlorodifluoromethane one sees the 2D skeletal structure of the compound as below This representation appears to be of a particular style that ...
2
votes
1answer
93 views

Help on alternative terpene names and naming schemes

I am a software developer and currently parsing data involving terpene profiles of plant samples. The data in question uses different ways of naming the same terpenes in-between samples and since this ...
0
votes
0answers
88 views

Experimental bond lengths and binding energies of diatomic molecules

Is it possible to find the experimental values of the bond length and the binding energy of the diatomic molecules $\text H_2$, $\text{Be}_2$, and $\text{Ar}_2$ in one source? I found a lot of ...
0
votes
2answers
96 views

How to find chemical market value [closed]

I would like to retrieve pricing information for specific chemicals. Is there a centralized resource for this? Edit: I want to clarify that this type of data is to conduct a techno-economic study. I ...
0
votes
1answer
351 views

Molar absorption coefficient of H2SO4(aq) for UV-vis spectrophotometry

I am wondering if there is anything in the literature that can tell me what is the molar absorptivity (i.e. molar extinction coefficient) of aqueous sulfuric acid at a given wavelength (in my case, I ...
5
votes
2answers
565 views

What is the correct regular expression for InChI?

When I look for a regular expression for InChI, I succeed on EBI's MIRIAM Registery website: ...
5
votes
3answers
215 views

What is the best way to convert SMILES strings to file names?

I would like to convert SMILES strings into file names. There are many characters to avoid in file names, i.e. \/:*?"<>| or maybe even ...
7
votes
1answer
123 views

Validation of _atom_site_frac_*: Range outside of [0,1)?

I have the following cif file ...
3
votes
0answers
80 views

Which organic compounds have the most strongly negative enthalpies of formation?

I've been using the NIST Webbook to list organic compounds and look at their heats of formation (kJ/g, not mol). If I limit myself to three carbons, I still get over 400 results. I can use some ...
1
vote
0answers
77 views

Where can I find a downloadable database of basic physical and chemical properties?

The web has many online databases of properties of compounds locked behind search interfaces, but I can't find anything you can actually download. I want a corpus of data that might allow me to, say, ...
1
vote
0answers
25 views

Deliquescence database

I am looking for a database or printed document providing the RH0 (relative humidity above which deliquescence will occur) for inorganic salts. I've looked everywhere on the internet can find nothing.
2
votes
1answer
2k views

Free chemical reactions database

I'm creating a program, which predicts reactions of compound. So, I need a database of chemical reactions. And I need both inorganic and organic reactions. But I can't use Scifinder or Reaxys because ...
5
votes
1answer
141 views

Algorithm used by PubChem to determine the 2D layout assignment for Compound entries?

The PubChem database provides 2D structures for entries in its Compounds database: ftp://ftp.ncbi.nlm.nih.gov/pubchem/Compound/ (ftp link to download examples) On the page linked below, under the "...
3
votes
0answers
470 views

Calculating Surface Area of Compound

Is there any way to calculate the surface area of compounds such as 2,5-dimethylhexane or 3-methylpentane? If not, is there a database that has information on surface area of these compounds (not ...
2
votes
1answer
166 views

Need help interpreting this data table (provided below)

I am confused about this data table. Can someone please explain how this person got a linear alkanes of differing molar masses? (I know some basics of organic chemistry, but I'm still learning.) Are ...
5
votes
1answer
219 views

Chemical time scales

In calculating UV/VIS spectra with computational procedures (say, TD-DFT), it is commonly assumed that the geometry of the ground-state is still valid also for the excited state due to the short time ...
4
votes
1answer
1k views

Is there an open Chemical database that includes GHS/CLP classifications?

I'm looking for a Chemical database that is up to date (via a firm, experts or crowdsourcing) is open and free to use (best via an API) contains the CLP/GHS classifications for chemicals I have not ...
0
votes
1answer
265 views

where can I find experimental compressibility factor values?

I am interested in experimental compressibility factors for various gases, such as methane and carbon monoxide. Not only for standard pressures and room temperature, but in a range from 1 to a few ...
6
votes
1answer
1k views

Finding cubic ice CIF files in crystal database

Could anyone please tell me where I could find the the structure of cubic ice (ice Ic) as a CIF file? I have been searching the cambridge structural database using "H2O", "water", "dihyrogen oxide" ...