Questions tagged [databases]

Use for questions regarding reference requests for a databases and information about databases

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Database of atomic crystal structure data or images of rocks and minerals?

I am looking for crystal structure images so I can redraw them in a nice form. However, I don't seem to find much searching Google. Perhaps this is a slightly better example (searching for Quartz ...
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Database of Resonance Structures

I am preparing to study organic chemistry in the coming year, and I had hoped to compile a list of practice questions for examining resonance structures. Is there an online database that holds the ...
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Full list of CAS numbers?

I'm trying to find a full list of CAS Registry Numbers, but it looks like it's not in open access. Is it a proprietary database that can't be downloaded easily?
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Data for Madelung Constants

Where can I find data for the Madelung constants for various ionic compounds? Specifically, I am looking at silicon tetrachloride, yttrium (III) chloride, zirconium (IV) oxynitrate hydrate, niobium (V)...
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Mapping of half-life decay for all elements/isotopes

Is there an open resource that helps illustrate all paths of decay for all isotopes (e.g. $\ce{^{99}Mo}$ decaying to $\ce{^\mathrm{99m}Tc})?$ I know the result state/transition map would be massive, ...
-4 votes
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Where can i find accurate bond angles?

I am trying to find places where I can have accurate bond angles of certain molecules such as $\ce{F2Se}$, $\ce{Cl2S}$, or even $\ce{S2Se}. I have looked everywhere and have found only 3 sources that ...
2 votes
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Unique notation to search for compounds in PubChem and in Chembl

I am not a chemist, I come from a computer science background. I am working on a project related to computer-aided drug design. I have a list of chemical compounds in their SMILES notation, to which I ...
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What Chemical Database Extensions for Structure and Similarity Search are there?

I am looking for extensions/add-ons for relational databases (RDBMS) that enable storing and handling chemical structures including the possibility for substructure searches and similarity search. I ...
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Where to find the ChEMBL21 database in CSV format?

I come from an artificial intelligence (AI) background (and not from chemistry). However, my Ph.D. thesis is about Deep Reinforcement Learning for drug design. From one of the most famous papers in ...
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1 answer
374 views

Databases for Enthalpy of Solution and Ionic Radii for Ionic Salts

I am looking to investigate the relation between experimental enthalpies of solution and theoretical enthalpies of solution calculated using theoretical equations for the lattice enthalpy and ...
2 votes
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g-tensor and hyperfine tensor for nitroxide spin label with 15N

Does anyone know where I can find numerical data for the $g$ tensor and hyperfine tensor for a nitroxide spin label where the nitrogen-14 atom has been replaced by a nitrogen-15 atom? I'm really ...
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Why is the enthalpy of formation of 2,2-dimethylpentane larger than that of 2,2,3-trimethylbutane?

Firstly, it is commonly known and taught that branched alkanes are more stable than linear ones, and so have larger enthalpies of formation. But why is that the case? Are there some steric ...
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Does PubChem have stereocenter location data?

I have spent the last couple of days learning to navigate, find useful information and use the download service on the PubChem website. One of the pieces of information you can find is a stereocenter ...
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Source for UV cut-off values of buffers

When I want to check a $\mathrm{p}K_\mathrm{a}$ value I look it up in CRC Handbook. Is there such source for UV cut-off values of various buffers? Usually books in chromatography contain tables with ...
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database for catalytic reaction mechanism

I am looking for a database containing detailed reaction mechanisms for (homogenous) catalytic reactions. Regular organic textbooks or papers generally draw some broad picture of how the mechanism may ...
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Where can I find literature values for standard molar enthalpies of neutralization?

I'm looking for enthalpy of neutralization literature values for inorganic weak acids. NIST, PubChem, etc. don't list them. Is there somewhere else I should look?
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IR absorption chart

I am taking a course in structural determination of organic compounds. Right now, we are giving the IR spectra. I am looking for a table, as detailed as possible, of the absorptions. I hope you can ...
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Fundamental vibrational modes for QM9 molecules

QM9 dataset contains about $134000$ small organic molecules with following properties computed using DFT approaches: ...
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API for molecular classification

We would like to identify an application programming interface (API) which can be fed a SMILES string, PubChem CID, IUPAC name or equivalent, which returns a set of strings corresponding to molecule ...
2 votes
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105 views

Equilibrium Constants for Diatomic Gases at High Temperatures

I'm new here and I haven't taken chemistry beyond high school, so please forgive the ignorance. I am reading a book about hypersonic aerodynamics, and I am trying to connect some chemistry knowledge ...
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Any large databases of IR Spectra that you are able to download many spectra in bulk [closed]

I am currently working on a machine learning project, in which I need access to many IR spectra, the more the better, in order to build a classifier that will used some unsupervised learning in order ...
1 vote
1 answer
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Are there any fluorophores with lifetimes in the micro to milli second range?

I'm looking for a fluorophore with exceptionally long lifetime to use in an oxygen optode (the longer the lifetime the less timing precision needed in the electronics). So far the longest I have ...
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API or database for verifying chemical reactions [closed]

Is there a database or API(rest calls) for verifying chemical equations? Example, Na + Cl -> NaCl + Loss of energy. So if I want to verify if there is a loss of energy or gain of energy? Is there ...
2 votes
2 answers
120 views

What are the GDB-13 criteria for "synthetically accessible organic molecules"?

I'm trying to understand the QM datasets (QM7, QM8, QM9), however, in the description of QM7 the data is described as follows: [The] QM7 dataset, which is a subset of GDB-13 (a database of nearly 1 ...
7 votes
2 answers
341 views

Open resource for spectroscopic raw data

Is anyone aware of reliable resources (ideally public) which allow the user to download the raw spectroscopic data such as infrared spectrum of small organic molecules, or rotational spectrum of HCl/...
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Does anyone know a database that shows the effect of electrolyte concentration on the production of hydrogen gas during electrolysis of water?

I'm currently studying in the International Baccalaureate model. This high school model asks their students to do an individual work called the Internal Assessment. One of the subjects I study is ...
3 votes
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Unique identifier for chemical substances?

One famous database for chemical substances is PubChem. If one reads the section about other identifiers than the PubChem ID for Ethanol one gets several CAS numbers (potentially deprecated ones as ...
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Energy cost of C−N rotation in hydroxamate group

I am looking for a literature reference on the energetic cost of C−N rotation in hydroxamate group such in LC5 in water. I have been googling for a while.
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Database for experimental diatomic ionization energies

I am looking for a database, in which the experimental ionization energies (and e.g. heat of formation) of atoms and diatomic molecules are listed as files. If it comes with a Python package, that ...
16 votes
3 answers
1k views

Are there any 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 ...
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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 ...
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1 answer
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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
1 answer
116 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 ...
6 votes
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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 ...
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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 ...
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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, ...
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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 ...
1 vote
1 answer
553 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?
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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
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178 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-...
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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 ...
3 votes
1 answer
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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 ...
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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 ...
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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 ...
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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 ...
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1 answer
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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 ...
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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: ...
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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 ...
5 votes
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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 ...
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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, ...