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Questions tagged [reference-request]

This tag is for questions looking for a single specific, or a small number of (citable) references.

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Resources for learning Chemistry

Based on various other Stack exchange site (Mandarin Chinese, Russian and German), we adapt this project here for chemistry, since it's a great idea to have all kinds of resources in one place. This ...
38 votes
1 answer
5k views

What would follow in the series sigma, pi and delta bonds?

I realise, that this question is a stretch, but I was wondering, how would a bonding orbital be called if it was formed from two $f_{x(x^2−3y^2)}$ or $f_{y(3x^2−y^2)}$ orbitals. Have there been any ...
Martin - マーチン's user avatar
25 votes
2 answers
3k views

Which is the currently accepted mechanism of a Wittig reaction?

The Wittig reaction is one of the most significant advances in synthetic organic chemistry in the 20th century and rightfully won its discoverer, Georg Wittig, the Nobel Prize in Chemistry. A Wittig ...
Jan's user avatar
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22 votes
3 answers
9k views

Conductivity as a function of acid concentration

I have conducted an experiment measuring the conductivity of both hydrochloric acid and sulfuric acid in solution respectively, with varying concentration. Wikipedia as well as a question on the site ...
user1997744's user avatar
9 votes
6 answers
8k views

Is there a database on chemical reactions, similar to NIST, but far more complete?

The only thing I'm interested in is to be able to search all reactions involving that compound in the database. Equilibrium constant, reaction rate and energy of activation would all be very welcome, ...
FinnTheHuman's user avatar
42 votes
4 answers
2k views

Do symmetric hydrogen bonds in neutral molecules exist?

As far as I know, there have only few truly symmetric hydrogen bonds been observed. Unquestionable is the existence of it in the bifluoride ion, $\ce{[F-H-F]-}$, see also here. There are a couple of ...
Martin - マーチン's user avatar
23 votes
3 answers
902 views

What is the isomer distribution in monosubstituted fluorobullvalene?

Bullvalene (tricyclo[3.3.2.02,8]deca-3,6,9-triene) is a fluxional molecule able to interconvert any two carbon atoms through a series of degenerate Cope rearrangements (for more information, see the ...
ron's user avatar
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25 votes
1 answer
4k views

Theoretical basis behind orbital correlation diagram for pericyclic reactions

When discussing pericyclic reactions, the Woodward-Hoffman rules allow one to predict whether a reaction will be thermally/photochemically allowed. This has been discussed in many questions on chem.SE,...
NotEvans.'s user avatar
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21 votes
1 answer
4k views

How can benzaldehyde have a pKa of 14.9?

There are numerous websites out there which claim that the pKa of benzaldehyde – C6H5CHO – is 14.90. (Just do a Google search for benzaldehyde pka to see what I ...
orthocresol's user avatar
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20 votes
5 answers
14k views

Which substance has the highest temperature range between melting and boiling point

Which substances exist that are normally liquid and that will not freeze nor boil even at relatively low/high temperatures as compared to the freezing and boiling points of water? Or how can I ...
Mr. Developerdude's user avatar
7 votes
1 answer
1k views

What is the chemical composition of Ferrous Ferrocyanide?

To this day, iron-cyanide complexes confuses me. So, I want to settle this once and for all. After scavenging the internet, I gathered the following result: $$ \ce{Ferr} \color{blue}{\ce{ous}}~\ce{...
Nilay Ghosh's user avatar
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6 votes
3 answers
7k views

Radius of hydride (H⁻) ion

What is the radius of the hydride $(\ce{H-})$ ion? There are several sources with conflicting reports on the same. Inorganic Chemistry: Principles of structure and Reactivity cites Pauling’s 1960 ...
Aniruddha Deb's user avatar
5 votes
1 answer
257 views

Has tellurium(II) iodide been properly characterized ever?

According to Wikipedia, tellurium tetraiodide decomposes on heating: $$\ce{TeI4 ->[\Delta] TeI2 + I2}$$ However, the reaction is somewhat wrong as according to this 2008 paper: Solid tellurium ...
Nilay Ghosh's user avatar
  • 26.3k
21 votes
5 answers
17k views

Where can I find a downloadable spreadsheet of element properties?

Sorry for the FAQ, but I really don't know where to find a full spreadsheet for element properties. I mean a table that has one row for each element, and the columns are its properties, such as name, ...
Mostafa Farzán's user avatar
18 votes
3 answers
5k views

Modern open-source tools for simulation of NMR spectra

I am interested in predicting the NMR spectrum of small organic compounds. It doesn't matter to me if the prediction is very accurate. I'll eventually be comparing the prediction to experimental ...
Curt F.'s user avatar
  • 22k
15 votes
4 answers
4k views

Public API for physical properties

Is there a publicly available API that serves physical property data for organic molecules? Pubchem does not serve properties, ChemSpider closes property access to API calls, and Toxnet only serves ...
pkmeh's user avatar
  • 151
13 votes
1 answer
1k views

Does the largest known cycloalkane contain 288 carbon atoms?

If you Google "largest known cycloalkane", you will find this: The above result came from a random HW-QnA site. From where does the result come from? Similar posts: Largest alkane having a ...
Nilay Ghosh's user avatar
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13 votes
1 answer
349 views

Newer ionic radii data than Shannon's 1976 compilation?

Shannon, R. D., 1976, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides: Acta Crystallographica Section A, v. 32, p. 751–767. DOI: 10.1107/...
Gimelist's user avatar
  • 5,452
11 votes
1 answer
2k views

What substance has the lowest solubility product?

What substance has the lowest $K_\mathrm{sp}$ and what is its value? The lowest I could find is $2.6\cdot 10^{-124}$ for cobalt(III) sulfide $\ce{Co2S3}$.
EJC's user avatar
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11 votes
4 answers
18k views

Reason for the formation of azeotropes

Why is it that some liquid mixtures (that exhibit positive/negative deviation from Raoult's law) form azeotropic mixtures at certain compositions? What is the physical reason behind this; are there ...
AADHI's user avatar
  • 127
10 votes
5 answers
2k views

How can I calculate the charge distribution of a water molecule?

I would like to obtain the 3D charge density of a water molecule for plotting purposes (i.e. not necessarily super-accurate). I know this is a tough problem, but I'd like to give it a try. Since I'm ...
uhoh's user avatar
  • 5,888
10 votes
3 answers
972 views

Free chemical database to search for physical properties?

I am looking for an Open-access tool that can search "backwards", eg. give me all the structures corresponding to a given heat of formation, critical pressure, etc. It would be even better if the ...
user avatar
9 votes
1 answer
3k views

How to choose proper active space in method such as CASPT2 and CASSCF?

I am confused about other research paper which use CASPT2 method. I am not clear about how to choose active space. What can I refer to? (tutorial reviews, papers, or any other things)
Chao Song's user avatar
  • 711
7 votes
2 answers
7k views

Hash and Wedge nomenclature

One of the first things learnt in organic chemistry is that wedged bonds can be thought of as bonds coming out of the plane of the paper towards you, and hashed bonds can be thought of as bonds going ...
NotEvans.'s user avatar
  • 17.2k
7 votes
1 answer
779 views

References for Transition State Theory and Quantum Transtion State Theory

Having asked recently this, I started to look for good references and notes on Transition State Theory and, also, modern versions of it including things like tunneling (which isn't taken into account ...
user avatar
7 votes
1 answer
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 ...
Willem Mulder's user avatar
6 votes
1 answer
9k views

Why is the standard enthalpy of formation of elements in their native forms zero?

Why is the standard enthalpy of formation of $\ce{O2}$ and other reference forms of elements equal to zero? Well, from what I know, bonding releases energy. Also, does anybody know a source for ...
most venerable sir's user avatar
5 votes
1 answer
214 views

Quotable Literature for the Enthalpy of a Proton

A proton obviously has no electronic energy, no vibrational and no rotational degrees of freedom. Therefore I think it is fair to assume, that $$H(\ce{H+})=\frac32\cdot \mathcal{R}\cdot T$$ holds for ...
Martin - マーチン's user avatar
4 votes
1 answer
1k views

What exactly does the "per mole" unit of heat of atomization mean?

I am facing a confusion in the definition of the standard enthalpy of atomization. The confusion arises because of the "per mole" in its units ($\pu{kJ mol^-1}$). My question: When I say "per mole", ...
Gaurang Tandon's user avatar
0 votes
0 answers
57 views

geometry of [Co(CN)₄]4-

This is a question that arises from the jee advanced 2024(india) exam. I am not sure whether the above complex exists.However it has been asked in the paper. in the exam we are supposed to use only ...
Ganesha Dattatraya Gaonkar CFA's user avatar
-2 votes
0 answers
91 views

Doubt in shape of [Co(CN)₄]4- compound? [duplicate]

I think the shape of [Co(CN)₄]4- should be square planar but am unable to find a reference from a reputed source on the internet?
Garv Chaudha's user avatar
40 votes
3 answers
2k views

Is Hexafluorocyclohexane the "Most Polar" Small Molecule?

Earlier this year, there was a lot of attention when all-cis 1,2,3,4,5,6-hexafluorocyclohexane was synthesized*: Notably, C&E News quoted the lead author: This compound is remarkable for being ...
Geoff Hutchison's user avatar
21 votes
1 answer
584 views

What are modern approaches to describe and/or quantify aromaticity?

I know that Schleyer described an approach for evaluating aromaticity using nucleus-independent chemical shifts (NICS, see e.g. Chem. Rev. 2005, 105 (10), 3842–3888) quite some time back. I also ...
logical x 2's user avatar
  • 2,794
20 votes
2 answers
15k views

What is the least dense liquid under normal conditions?

What is the least dense liquid under normal conditions, room temperature, one atmosphere of pressure, doesn't combust upon contact with air, also wouldn't kill a human just for being in the same room ...
user78390's user avatar
  • 201
19 votes
1 answer
829 views

What did actually happen when Staudinger tried to synthesise diamond?

It is a famous reaction that used to be a teaching lab experiment, but is now banned in Germany, because it is too dangerous. To quote-translate quite liberally from the German www.seilnacht.com: ...
Martin - マーチン's user avatar
18 votes
3 answers
3k views

What is the formally correct notation of t-Bu, i-Pr, p-NO2, n-Bu, a-HCl, etc.?

In chemical notation, can I safely assume that the notation of a single lower-case latin character followed by a hyphen followed by an Element upper-case latin character (and possibly more characters)...
mhchem's user avatar
  • 3,316
13 votes
2 answers
3k views

What is "chemical pressure"?

While reading some publications on solid superconductors, I encountered a term "chemical pressure" a few times, which is usually attributed to the changes of superconducting transition ...
andselisk's user avatar
  • 38.3k
12 votes
3 answers
51k views

Does milk drinking prevent long-term chemical poisoning?

I have heard some rumors that drinking milk prevents chemical poisoning. I have done a bit research and some sources confirm that. Corrosive Poisons The best first aid is to dilute the poison as ...
Jaroslav Kotowski's user avatar
11 votes
1 answer
310 views

Which electronic effects are responsible for the reduction of nucleophilicity of a hydroxy group orthogonal to an ester?

I am facing a similar synthetic problem as Boekman Jr. et al noted in their synthesis of Tetronolide.[1] I will quote their’s rather than disclosing my actual synthetic problem, but note that the key ...
Jan's user avatar
  • 68.3k
11 votes
1 answer
1k views

Is isobutyl chloride or ethyl chloride more reactive in an SN1 reaction?

Compare the rate of $\mathrm{S_N1}$ reaction in the following compounds: We see that both compounds form primary carbocations. However, there is more hyperconjugation in the second compound as ...
Akshat Joshi's user avatar
11 votes
1 answer
1k views

What are the most extreme chemicals?

Some chemicals certainly have extraordinary properties. One can consider them extreme in a sense, that they are the prime example for a concept, or they achieve the highest or lowest values in a ...
10 votes
3 answers
3k views

What is "super" in superphosphate?

This question is inspired from a previous question(marked unclear). I don't know the context of that question but I was intrigued by a statement: Superphosphate is used instead of just phosphate ...
Nilay Ghosh's user avatar
  • 26.3k
9 votes
1 answer
667 views

What are introductory level books on chemical engineering?

I'm currently enrolled in a chemical engineering course in my college, and in my first year, I'd like to get a nice introductory book on that field of study. I'd prefer that the book covers several ...
Pritt says Reinstate Monica's user avatar
8 votes
1 answer
399 views

Tunneling corrections in reaction rates

I've studied Transition State Theory since I asked this a while ago, but so far I have not been able to find a detailed explanation of how tunneling corrections are implemented into reaction rates ...
user avatar
8 votes
1 answer
2k views

Difference between single point energy and dimerization energy

I am investigating potential energy surface characteristics of some electrostatic monomeric interactions e.g. $\ce{F-H}$...$\ce{F-H}$. I'm using DFT and SCS-MP2 to perform the necessary calculations ...
diffracteD's user avatar
7 votes
2 answers
9k views

What is the Ksp of Al(OH)3?

Top hits on google are: This site Aluminum hydroxide $\ce{Al(OH)_3}$ >> $ 1.3×10^{–33}$ and This site Aluminum hydroxide $\ce{Al(OH)_3}$ >> $ 3×10^{–34}$ which is different by a ...
Dexter's user avatar
  • 71
7 votes
1 answer
917 views

UV/Vis spectroscopy transition reference

There are mainly fundamental transitions happening during excitation and UV/Vis spectroscopy (as n- > σ* ,π->π* ,n- > π ,..). I am looking for a good reference that shows these transitions for ...
Aug's user avatar
  • 2,141
7 votes
1 answer
598 views

How is the vibration of multiple atoms treated in vibrational spectroscopy?

Most of the advanced undergraduate textbooks on physical chemistry/ instrumental analysis show the case of a diatomic harmonic oscillator and derive formulae for predicting the frequencies. The ...
ACR's user avatar
  • 41.3k
6 votes
2 answers
8k views

Reaction of borax with NaOH

How does borax react with NaOH? My textbook says that sodium peroxoborate is formed. I couldn't find the reaction anywhere else. Can anyone verify as well as explain it?
user avatar
4 votes
1 answer
320 views

Approximate magnetic susceptibility of these liquid propellants?

This question asks if the comparatively large paramagnetic susceptibility of liquid oxygen (LOX) is considered when designing rocket tank and engine systems. This comment suggests fuels such as RP-1 (...
uhoh's user avatar
  • 5,888