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In the original 1771 experiment, Scheele used a very simple setup consisting of a glass retort with a glass receiver (round-bottom flask). Yes, the glass was etched to some degree by the fumes, but it was not drastic enough to destroy the apparatus. From Anders Lennartson's The Chemical Works of Carl Wilhelm Scheele [1, p. 22]: 3.1 Publication 1. ...

31

tl;dr: I don't think there is any mechanism that is 100% correct, and, in cases like this especially, I think it would completely depend upon what set of carbonyl/ylid/base/solvent etc. was used. But, of course, we like being able to generalise, and to my knowledge theres a lot more evidence to support a concerted type mechanism. General Background The ...

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Books about Inorganic Chemistry General texts Housecroft, C. E.; Sharpe, A. G. Inorganic Chemistry, 4th ed.; Prentice Hall: Upper Saddle River, NJ, 2012. Weller, M.; Overton, T.; Rourke, J.; Armstrong, F. Inorganic Chemistry, 6th ed; Oxford UP: Oxford, U.K., 2014. This is the latest version of the textbook commonly known as Shriver & Atkins. Miessler, ...

26

EZ-water is not a breakthrough. It is not new, nor is it valid. This appears to be one of the many claims about the healthful benefits of drinking "ionized water". The original "article" linked, contains a number of misleading . Water molecules make up 99% of your body. This is true, but misleading. According to various sources, the human body is between ...

25

At first, I thought, that those 6.2 D of O’Hagan et al. have been measured somehow but it as later described, they calculated it (1): A molecular dipole value of 6.2 D for 1 was calculated at the M11/6-311G(2d,p) theory level using natural bond orbital (NBO) analysis with NBO 6.0. I was using your given database for a little search, starting with ...

22

Video Resources (online) The University of Nottingham's Periodic Videos The periodic table of videos includes introductions to all elements. The molecular videos section focusses on interesting chemical reactions. Apart from having quite some entertaining value, they visualise a lot of reactions that can only safely be carried out in a laboratory ...

19

Extensive NMR studies of substituted bullvalenes were done in the 1960's and 70's, by Oth et al. Much of their original work was published in German. Thankfully, some of these topics were revisited (in English!) during the 1990's by Luz et al., and these included some rather nice low temperature 19F and 13C NMR studies in both solution and solid state (and ...

19

tl;dr The next in the series is called φ bond. There is even a tiny Wikipedia article about it. Nicolau pointed me to the Wikipedia article, that had at the time a tiny section about the φ symmetry of the bond. Ben also kindly agreed with my naming proposition. I'd like to back up just a little bit an quote one sentence of this article: The type ...

19

Wolfram company doesn't conduct any experimental determinations of physical constants for chemical compounds and uses literature data sources. The webpage for ChemicalData Source Information lists numerous sources of chemical information used by the company's products, including Wolfram Alpha. Wolfram Alpha Knowledge Database is linked with 87th ed. (2006) ...

18

Introduction Instead of the usual cycloadditions (which has some extra complications in terms of the reacting orbitals), let's consider the concerted reaction $\ce{H2 + D2 -> 2HD}$. We'll come back to the cycloadditions at the end. occurring via a square planar transition state. This can be analysed with the W–H rules and you'll find that it's a ...

17

Gallium melts at 30 °C but doesn't boil until 2200 °C. If 30 °C is a bit too warm to count as "room temperature" or "normally" for you, I found an old paper that recommends tetralkyl silanes such as tetradodecyl silane as lubricants that are liquid over very wide temperatures. Addendum: Dowtherm A is a eutectic mixture of biphenyl and diphenyl ...

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Books about Analytical Chemistry Schwarzenbach, G.; Flaschka, H. A. Complexometric Titrations; Methuen: London, 1957 (translated by H. Irving in 1969). Skoog, D. A.; West, D. M.; Holler, F. J.; Crouch, S. R. Fundamentals of Analytical Chemistry, 9th ed.; Brooks/Cole: Pacific Grove, CA, 2013. Books about Biochemistry and Chemical Biology Voet, D.; Voet, J. ...

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It appears that symmetric hydrogen bonds can exist between neutral molecules, even between water molecules! But it takes 60 GPa of pressure to make water to bond like that. Article named very descriptively "Compression of Ice to 210 gigapascals: Infrared Evidence for a Symmetric Hydrogen-Bonded Phase" proves it: Protonated and deuterated ices ($\ce{H2O}$ ...

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In the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), single italic lower-case Latin letters are used in some stereodescriptors (such as ‘c’, ‘m’, ‘p’, ‘r’, ‘s’, and ‘t’), in descriptors for fusion sites (e.g. dibenzo[c,g]phenanthrene), in locants (‘o’, ‘m’, and ‘p’ in place of ortho, meta, ...

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Let me begin by thanking Martin and long for supplying the key reference (J. Am. Chem. Soc. 1996, 118 (34), 7995–8005). Importantly, long also provided the isomer ratio I was asking for; according to him, the ratio was estimated using the numbers at bottom of page 7997 (with the 0.002 added). The free energy differences between the isomers of ...

15

At first I checked common organic compounds and solvents in CRC Handbook [1, 9-59] that have dipole moment above $\pu{4.5 D}$: \begin{array}{llrr} \text{Name} & \text{Formula} & \text{Atom count} & \mu, \pu{D} \\ \hline \text{Thiophenecarbonitrile} & \ce{C5H3NS} & 10 & 4.59(2) \\ \text{3-Methyl-2-butenenitrile} & \ce{C5H7N} & ...

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Online Courses UC Davis' ChemWiki: The Dynamic Chemistry Hypertext The ChemWiki is a collaborative approach toward chemistry education where an Open Access textbook environment is constantly being written and re-written by students and faculty members resulting in a free Chemistry textbook to supplant conventional paper-based books. Jim Clark's Chemguide An ...

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This question crossed my mind during a lab today because we were making $\ce{Ni(dmg)2}$, which is shown below. Well first, this is charged in some sense, but it is net-neutral. Also, the configuration shown above is only one way to draw it, and it seems as if everything should be symmetrical and thus that hydrogen should be equally shared between the two ...

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Densest gas Densest element Greatest range between melting and boiling temperature Highest melting point Lowest solubility product constant Most dangerous: Is there any substance that's a 4-4-4 on the NFPA diamond?. But also, don't forget that the NPFA diamond doesn't even classify ClF3 as flammable (though everything else is flammable in it) and by any ...

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The term superphosphate is really old, even well before the concept of atoms was proposed by Dalton. Therefore it is difficult to rationalize the choice of this terminology. In the unabridged version of the Oxford English Dictionary, you can see the earliest usage dates back to 1798 Chemistry. A phosphate containing an excess of phosphoric acid; an ...

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Books about General Chemistry Atkins, P. W.; Jones, L. L.; Laverman, L. E. Chemical Principles: The Quest for Insight, 6th ed.; W. H. Freeman: New York, 2012. Silberberg, M.; Amateis, P. Chemistry: The Molecular Nature of Matter and Change, 7th ed.; McGraw-Hill: New York, 2014. Oxtoby, D. W.; Gillis, H. P.; Campion, A. Principles of Modern Chemistry, 8th ...

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Software ChemOffice Professional Commercial software for drawing molecular structures, 3D models and many more. High price but most higher education institutes will provide students/staff with free institutional licenses. MarvinSketch Freeware (closed-source) for drawing molecular structures with a wide feature set. In addition to just being able to draw ...

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A red gold sol is a colloidal suspension of gold nanoparticles with average size of particles less than 100 nm. The suspension is quite stable — the nanoparticles don't aggregate because of the existence of an electrical double layer on the surface of particles which causes electrostatic repulsion between the particles. If you add a sufficient amount of an ...

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Significant amount of geminal diol of benzaldehyde exists in an aqueous solution of benzaldehyde at 25 °C because $\mathrm{p}K_{\text{hyd}} = 2$ (Ref. 1) The $\mathrm{p}K_{\mathrm a}$ of benzyl alcohol is listed as 15.40 (Wikipedia). Thus, one can reasonably assume that the given value of $\mathrm{p}K_{\mathrm a}$ 14.9 represents a composite equilibrium ...

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Based on research inspired by andselisk's answer, chemists stored it in glass vessels coated in wax (similar to the receiver setup Scheele used to prove the silicon dioxide precipitate was from the glassware itself. The fourth paragraph down in this blog post on The Chronicle Flask touches on it (emphasis mine): Where do you put something that eats ...

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I had some free time and resources at hand and did some highly accurate quantum chemical calculations for this system. I took it as a chance to compute some benchmarks and play a little with density functional theory. Originally I also wanted to compute transition barriers, but based on the previous findings I had to omit that, since I currently cannot ...

12

Just because an organism might need a nutrient, whether arsenic or cobalt (which homo sapiens needs for making RBC's) does not mean that the organism is not carbon-based. What had been announced was that an organism used arsenic to replace phosphorus, not carbon, which has since been amended. There is also the question whether the GFAJ-1 microbe is a ...

12

The polar aprotic solvents (for example dimethylformamide, mp −61 °C, bp 153 °C, or hexamethylphosphoramide, mp 7 °C, bp 230–232 °C) would be a place to start. Silicone oil is often used in heating baths – one product in the Aldrich catalog is advertised as having a working range of −40 °C to +230 °C.

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I'm studying chemical engineering for more than two years and what I can tell you is that is not really a lot of "good" books you may read as an introduction. You have to understand that Chemical Engineering contains both "Chemical" and "Engineering". The first one refers to chemistry whereas the second refers to the way to make something. I mean a ...

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An Intro in Russian edition of Reactivity of Inorganic Substances by Lidin et al. claims its uniqueness: Настоящее пособие носит информационно-справочный характер, не имеет аналогов в отечественной и зарубежной химической литературе, охватывает все разделы неорганической химии, изучаемые в химических вузах. (English) This reference handbook has no ...

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