Questions tagged [optical-properties]

Questions related to color as well as the reflecting and refracting properties of chemicals.

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Higher Experimental Optical activity compared to literature values [closed]

If you have a sample of an optically active substance it has a specific angle of rotation. Lets say the substance I produced had a value of 56 degrees but the literature value for my substance should ...
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1answer
55 views

Which of the following isomers of 2,3‐dihydroxy‐4‐methoxy‐4‐oxobutanoic acid are identical?

Which of the following are identical? A and B are identical A and B are diastereomers A and C are enantiomers A and B are enantiomers What I know is that when we rotate a ...
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What gas would be suited best to form a density gradient in a long tube? [closed]

I want to set up an aero-optics experiment using a sealed ~5 m length of pipe with a gas inside. The gas must form a density gradient, and must be transparent enough to view a target at the other end ...
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1answer
35 views

When to permute two times to find optical configuration [closed]

I'm learning about S and R configuration, and I know that in case where the 4th substituant is not behind we should permute it with the one which is behind. then we find the new configuration and use ...
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6answers
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Is there a commercial liquid with refractive index greater than n=2?

For an application I need a commercial, transparent liquid with refractive index $n>2$. Is this kind of liquid available? What's the chemical composition of this? On the web, only $n=1.81$ is ...
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1answer
81 views

Conditions for molecular dissymmetry

In my textbook, under the topic "Asymmetric and Dissymmetric Compounds", the following statement is given: A molecule which does not possess plane of symmetry, centre of symmetry, and alternating ...
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1answer
126 views

Is methanol optically active?

Strictly on theoretical basis, not based on experimental results. I can very well be wrong, but I think that methanol should be optically inactive because it has a plane of symmetry passing through ...
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2answers
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1answer
36 views

Is there a relationship between loss of electrons and EM wave reflection? [closed]

Is there a relationship between the loss of electrons in a cation and the amount of electromagnetic spectrum, a compound of this cation would subsequently reflect or transmit? For example, any ...
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83 views

What would superionic water ice look like?

Phys.org's Giant lasers crystallize water with shockwaves, revealing the atomic structure of superionic ice links to Nature Physics: Experimental evidence for superionic water ice using shock ...
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1answer
132 views

How to detect nM levels of Copper(I) Oxide in blood?

I'm trying to design an experiment to detect nM quantities of Copper(I) Oxide in fish blood. Are there any specific tests for Copper(I) Oxide that can be used to detect trace quantities(~nM)? Any non-...
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24 views

A formula for the refractive index of a gas dependent on temperature and pressure

I am in search for a formula that gives me the refractive index of a gas at a given temperature and pressure. Does such a formula exist? Ideally the solution should have this form: $n_g(t, p) = \...
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1answer
67 views

Would Z and E isomers show different optical activity?

Consider this compound, which is in E configuration and that red asterik denotes the chiral carbon. If I were to somehow cause the E-configuration of the alkene part to Z-configuration keeping the ...
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1answer
38 views

Synthetic ruby - damaged by heat less than its melting point?

A bit of a jewellery question but chemistry related. I want to encase a synthetic ruby (corundum, Al2O3) in silver by melting the silver around it. Either in a furnace or by casting. The MP of silver ...
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1answer
108 views

Optical activity [closed]

I was studying about the optical activity of compounds. And I found , it is written that the chirality of a molecule is the necessary and sufficient condition for a molecule to be optically active. I ...
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2answers
612 views

Can we rotate a mirror image by any angle to check if it is superimposable? [closed]

A molecule is chiral when it is different from its mirror image, and achiral if it is identical to its mirror image. To check if the mirror image is identical to the original object, we have to check ...
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1answer
44 views

What is the refractive index of poly(methacrylamide)?

I've been looking for the index of refraction for poly(methacrylamide). I searched several vendors and in https://polymerdatabase.com/ with no success. Is there any database where I can find this ...
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44 views

How to align povidone-iodine molecules in order to look for optical polarization

In this answer I mention how early polarizing filters (e.g. sunglasses) were made by doping a polymer with iodine atoms and then stretching the film to orient the polymer molecules. Electrons donated ...
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158 views

What compound has the strongest optical rotation of polarised light?

A question recently asked here whether compounds know to be chiral can have non-measurable optical rotations: Are there chiral compounds that don't rotate plane-polarized light?. Apparently they ...
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1answer
606 views

Are there chiral compounds that don't rotate plane-polarized light?

I know that meso compounds have chiral centers but don't rotate plane-polarized light, and I know that there can be non-traditionally chiral compounds (e.g. ones with large substituents that prohibit ...
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3answers
269 views

Can two lone pairs in different orbitals make a chiral centre?

Is it possible that if the two lone pairs in a molecule occupy different orbitals, then could this make the molecule chiral? What I mean is, suppose a carbon atom is attached to two different atoms ...
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2answers
716 views

Why does 1,3-dichloropropane not show stereoisomerism?

It is a multiple choice question: Which compound does not show stereoisomerism? A 1,2-dichloroprop-1-ene B 1,2-dichloropropane C 1,3-dichloroprop-1-ene D 1,3-dichloropropane I ...
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1answer
2k views

What happens when (+) 2-iodobutane is treated with NaI in acetone?

After treating the compound with NaI, we should follow SN2 mechanism and the product will follow an optical inversion, giving us (-)2-iodobutane, but the answer is (±)2-iodobutane. After going ...
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1answer
806 views

How is Volume an Extensive Property? [closed]

Based on the following definitions, can anyone explain why volume is an extensive property? Extensive Property: Properties that depend on the amount of matter in a sample. Volume: the amount of ...
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2answers
676 views

Why is FEP transparent and PTFE not?

fluorinated ethylene propylene (FEP) is close relative of poly(tetra-fluoroethylene) (PTFE), both only contain fluorine and carbon atoms,both have very similiar properties yet FEP is relatively ...
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1answer
861 views

How is polarization of light measured?

Chiral molecules are classified as dextrorotatory (+) or levorotatory (-) depending on whether they rotate plane-polarized light (ppl) to the right or left. My question is, how is such a measurement ...
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1answer
116 views

Does alumina become transparent at high temperatures?

Consider a normal opaque alumina crucible. I've heard that they become transparent at higher temperatures and therefore, are not appropriate for high precision DSC (caloric) measurements. The reason ...
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1answer
171 views

How many stereoisomers can exist for 4,5-bis(3-hydroxyoct-1-en-1-yl)cyclopentane-1,3-diol?

Q.10 For the given compound $\ce{X}$, the total number of optically active stereoisomers is ____. This is from JEE Advanced 2018 second question paper. I thought the answer to be at least 32 ...
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2answers
1k views

Meso and achiral does both term means the same?

When a molecule has plane of symmetry, or centre of symmetry it is termed as an achiral compound (though it contain some chiral centres). Same goes for the meso compounds due to the internal ...
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3answers
166 views

When an electron returns to it's ground state does it release the same wavelength of light that promoted it in the first place?

If this is true, I fail to understand why we see colour at all -- wouldn't any wavelengths absorbed by electron promotion be inconsequential to colour because there would an equal amount, and ...
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1answer
105 views

What does it mean if I am unable to write RS configuration for a compound?

We had to write all possible optically active monochloro derivatives of 2-methylbutane. I was unable to write RS configurations for 1 and 3, since they have carbon atoms with more than one same groups ...
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1answer
58 views

Intensity of “surface plasmon resonance “ absorption peaks for a nano-rod

The SPR absorption spectrum of a nano-rod is seen to have two peaks with the longer wavelength peak corresponding to the absorption by the longitudinal plasmons and the other to the transverse ...
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48 views

Is it possible to have a fully opaque 'switch glass'?

Current switch glass (smart glass) technology permits for a transparent glass to become semi-transparent, i.e., translucent. For my application, I was wondering if it was possible to make a 'smart ...
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1answer
945 views

Conditions for Chirality in optical isomerism [duplicate]

Is it necessary that any atoms which is chiral must have 4 different atoms around the central chiral atom(maybe it can be carbon if it's organic molecule) bonded to it? More specifically: I mean can't ...
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Effect of direct exposure to sunlight on various drugs

Today, we were discussing optical activity in class and our teacher said that some drugs are kept in dark coloured bottles to avoid direct exposure to sunlight. Same is the case with some other drugs ...
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1answer
409 views

Refractive index of barium sulfate

What is the refractive index of barium respectively where do I find it? I only find values for alpha, beta and x-ray radiation like on https://pubchem.ncbi.nlm.nih.gov/compound/barium_sulfate#section=...
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1answer
109 views

Optical techniques for kinetics studies

What optical methods can be used to measure the concentration of reacting gases in a reactor during an exothermic and fast reaction? I need to monitor and measure the local concentration of my gases (...
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1answer
923 views

How to think of solvated electrons?

This excellent answer explains at length what's happening in this fascinating video entitled Liquid Electrons - Periodic Table of Videos. In the screenshot below, the metallic-looking solvated ...
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1answer
194 views

How do I run MP2 and/or CCSD-level hyperpolarizability calculations with GAMESS?

I have used GAMESS before for TDHF (RPA) / TDDFT level first hyperpolarizability ($\beta$) calculations. However, I cannot figure out how to calculate $\beta$ with MP2 and CCSD for comparative ...
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1answer
295 views

How do chemical bonds increase molecular refractivity?

I see that the molecular refractivity of a compound consists of the refractivity indexes of its composite atoms and chemical bonds, and that the refractive index $n$ of a substance increases with its ...
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2answers
127 views

Permanent cloudy colloid with water

I need to make a cloudy white liquid where the particles won't eventually settle out. It will be exhibiting the Tyndall effect for a very long time. I'd use milk, but I don't want it to become rancid....
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1answer
372 views

D-Threose: reduction and optical activity

I've bumped into this exercise: Judging by the mechanism of reaction between D-threose and $\ce{NaBH4}$, do you think the final product will be optically active? To me looks like a reduction, ...
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1answer
66 views

Finding a substance which has a continuous gradient in refractive index

I need to find a substance whose refractive index is constantly changing and directly proportional to the square root of the depth. I know I'm looking for a lot, but I'd really appreciate any ideas or ...
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0answers
39 views

Is there any molecule describable by three-level with mixed parity and transition dipole moments in different directions?

I would like to know if there are molecules described by a three-level system with mixed parity and transition dipole moments in different directions. By mixed parity I mean all three transitions can ...
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1answer
982 views

What is happening in this video of solvated electrons donated from sodium in ammonia?

I just saw the Periodic Video Liquid Electrons - Periodic Table of Videos where sodium is added to liquid ammonia. The demonstration shows that even if electrons are solvated, if you have a high ...
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1k views

Home science optical absorption test for approximate caffeine quantity in coffee?

I started with How can you measure the caffeine content of a liquid at home? in the cooking stackexchange, but the test strips were only qualitative (yes/no) and don't seem to exist anymore, and the ...
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1answer
233 views

Discovery of optical activity of enantiomers - where did the idea of using polarized light came from?

According to Wikipedia, optical activity was first observed in 1811 in quartz. Louis Pasteur's contribution is also mentioned there and in other sources as a major advancement in establishing optical ...
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1answer
207 views

Optical activity of starch

I found this beautiful picture of starch granules in this German Wikipedia article about optical activity. Unfortunately, I have no idea what am I looking at. What are these crosses and why are they ...
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Is optical activity of a given compound a statistical picture?

When optical activity is taught it is done in terms of single molecules. But when it is actually measured it is done on a large collection of such molecules. So, how does the asymmetry manifest itself ...
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1answer
183 views

Suggestions for 200-600 nm range transmitting polymers/materials

I am a student of physics who is doing research related to Cherenkov measurements. For that purpose, I need suggestions for some materials that have the following properties: $80\%$ transparency in ...