Red Pigment and Ruby

choi

This posting contain many superscripts and subscripts (for chemical formulas, for example) that can not be rendered in the site, because there is no such function here. You may have to read the originals whose links are supplied.


Pigments | Studying Scarlet; A team of chemists are searching for a new red pigment. Economist, July 13, 2019
https://www.economist.com/scienc ... r-a-new-red-pigment

Quotations after paragraph 2: "Mas Subramanian, a material scientist at Oregon State University * * * In 2009 * * * [discovered] a powder as brilliant as a bluebird's wing. YInMn (pictured), as it is now known , was the first blue discovered for two centuries.  The perfect red has so far eluded Dr Subramanian -- in part because it is hard to predict the colour of a material before you make it. Small alterations to a crystal's structure structure can dramatically alter which parts of the spectrum that crystal absorbs and which it reflects. The green of emeralds and the red of rubies, for instance, are both caused by chromium atoms, but the atoms in question are bonded into their respective lattices in different ways.

Note:
(a) paragraph 2: "Other red pigments, meanwhile, either start off dull (oxides of iron) or fade to dullness unless given special protection from ultraviolet light (Pigment Red 254, the source of Ferraris' characteristic scarlet livery)."
(i) Michael Norman, The Story Behind Pigment Red 254, Nicknamed 'Ferrari Red.' Cleveland: Plain Dealer, Oct 23, 2007 (blog)
http://blog.cleveland.com/pdextra/2007/10/pollock_cuts.html
("many Ferrari models * * * have sported a coat of bright red paint made by Ciba Specialty Chemicals. * * * Ciba Specialty Chemicals, based in Basel, Switzerland, revolutionized the automobile paint industry when it patented the first known method of producing the pigment in 1983. * * * The pigment is based on an organic compound called DPP, first known to have been synthesized in 1974 by Michigan State University chemistry professor Donald G Farnum. * * * Before Pigment Red 254 appeared on the market in the late 1980s, red paint used by auto manufacturers tended to fade and develop a dusty look known as 'chalking.' The new pigment, in comparison, was extraordinarily bright, stable and resistant to ultraviolet light and extremes of heat and cold.  Nicknamed 'Ferrari Red' * * * ")
(ii) diketopyrrolopyrrole dye
https://en.wikipedia.org/wiki/Diketopyrrolopyrrole_dye
is composed of 2 keto group and 2 pyrroles.
https://en.wikipedia.org/wiki/Pyrrole

(b) YInMn is made up of elements yttrium (Y), Indium (In) and manganese (Mn).
(c) Emerald (or beryl with chromium3+ as impurities) does not have a east-to-understand crystal lattice (it is hexagonal) in the Web. The best I can find is Figure 1 of
Mitchell G Mihalynuk and Ray E Lett, Composition of Logtung Beryl (aquamarine) by ICPES/MS : A Comparison with Beryl Worldwide. British Columbia Geological Survey 141, Geological Fieldwork 2003.
https://pdfs.semanticscholar.org ... e36242e12152402.pdf

(d) "the red of rubies"
(i) Ruby has chemical formula Al2O3 with impurities of chromium3+ (the same as Aluminum3+).
(ii) Al2O3: Corundum Crystal Structure. Clear Science! July 20, 2010.
https://clearscience.tumblr.com/ ... nd-about-how-rubies
("when Al shares 3 electrons it then has no unpaired electrons. * * * A Cr sharing 3 electrons still has unpaired electrons, which can interact with light")
(A) electron shell
https://en.wikipedia.org/wiki/Electron_shell
(The electrons in the outermost occupied shell (or shells) determine the chemical properties of the atom; it is called the valence shell; section 3 Subshell; section 4 The electrons in the outermost occupied shell (or shells) determine the chemical properties of the atom; it is called the valence shell)
(B) chromium
https://en.wikipedia.org/wiki/Chromium
("The name of the element is derived from the Greek word chrōma, meaning color, because many chromium compounds are intensely colored. * * * Chromium is the fourth transition metal found on the periodic table, and has an electron configuration of [Ar] 3d5 4s1. It is also the first element in the periodic table whose ground-state electron configuration violates the Aufbau principle")

The Ar stands for argon. "[Ar] 3d5 4s1" means chromium has electron configuration of argon PLUS "3d5 4s1" -- so that the notation can be short.

"The aufbau principle * * * states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s shell is filled before the 2s subshell is occupied. In this way, the electrons of an atom or ion form the most stable electron configuration possible. * * * The principle takes its name from the German, Aufbauprinzip, 'building-up principle,' rather than being named for a scientist. It was formulated by Niels Bohr and Wolfgang Pauli in the early 1920s."  en.wikipedia.org for "Aufbau principle."

German-English dictionary:
* Aufbau (noun masculine; from [prefix] auf- [up] + [noun masculine] Bau [building, construction]): "construction"
https://en.wiktionary.org/wiki/Aufbau
* Prinzip (noun neuter): "principle"
https://dict.tu-chemnitz.de/ding ... inzip&iservice=

The English noun principle is, ultimately, "from Latin [noun neuter] principium beginning, from princip-, princeps initiator [from the Latin pairm English noun prince descended]."
https://www.merriam-webster.com/dictionary/principle