Skip to main content


A comprehensive List of Chemistry Blogs

All Things Metathesis Amphoteros Andre The Chemist Atoms And Numbers B.R.S.M. Behind NMR Lines Berate My Professor Blog Syn Central Science Chembark Chemcrowd Chemical Connections Chemically Cultured Chemistry And Life | Medicinal Chemistry. Pharmacology. Toxicology. Environmental Sciences. Chemistry Blog Chemistry Job Blog Chemistry Reflux Chemjobber Colorblind Chemistry Compound Interest Crows And Cats Curly Arrow Endless Possibilities V3.0 Everywherechemistry Explosci Flavor Scientist Geeky Girl Engineer Greenchemblog In The Pipeline Interesting Organic Chemistry And Natural Products. | Just Another Chemistry Site It's The Rheo Thing Kentucky Chemistry Kromablography Lostinscientia.Wordpress.Com/ Master Organic Chemistry Modern Steroid Science Must Love Science Naturalproductman's Blog New Reactions Not The Lab (NTL) Open Flask Org Prep Daily Organic Chemistry Tips And Techniques Organic Synthesis Insight Philosophically Disturbed Picture It... Pictures

Flippin–Lodge Angle

The Flippin–Lodge angle (FL angle) is one of two angles used by organic and biological chemists studying the relationship between the structure of molecules and ways that they react, for a particular common type of chemical reaction. The angles—the Bürgi–Dunitz (BD) and the Flippin–Lodge (FL)—describe the "angle of attack" of an electron-rich reactant, the nucleophile, with an electron-poor reactant, an electrophile, in particular when the latter is planar in shape. This is called a nucleophilic addition reaction and it is plays a central role in the biological chemistry taking place in the biosyntheses of metabolism, and is a central reaction "tool" in the toolkit of modern organic chemistry for constructing new molecules such as pharmaceuticals. Theory and use of these angles falls into the specialty of physical organic chemistry, which deals with chemical structure and reaction mechanism, in particular, the area called structure correlation. [more at wikipedia

Knot Theory and 3-manifolds

Read more at Wikipedia Article: Suggested Readings:  Dale Rolfsen's book, Knots and Links , (good introductory source)

Principle of minimum structural change

According to this oversimplified principle, chemical species do not isomerize in the course of a transformation, e.g. substitution, or the change of a functional group of a chemical species into a different functional group is not expected to involve the making or breaking of more than the minimum number of bonds required to effect that transformation. For example, any new substituents are expected to enter the precise positions previously occupied by displaced groups.[1] Molecular rearrangements[2]  violates the so-called 'principle of minimum structural change'. References:  IUPAC Goldbook, doi:10.1351/goldbook.M03997 The term is traditionally applied to any reaction that involves a change of connectivity (sometimes including hydrogen)

Abegg's rule

Abegg's rule states the sum of the absolute values of the maximum positive and negative valence of an atom is often equal to eight .   Abegg’s rule is sometimes referred to as "Abegg’s law of valence and countervalence". for a given chemical element (as sulfur) Abegg’s rule states that the sum of the absolute value of its negative valence (such as −2 for sulfur in H 2 S ) and its positive valence of maximum value (as +6 for sulfur in H 2 SO 4 ) is often equal to 8. The rule used a historic meaning of valence which resembles the modern concept of oxidation state in which an atom is an electron donor or receiver. Abegg, Richard Wilhelm Heinrich January 9, 1869 – April 3, 1910 Danish chemist, major work on chemical valence Trained as organic chemist (student of August Wilhelm von Hofmann at the University of Berlin); but practiced  physical chemistry with Friedrich Wilhelm Ostwald in Leipzig, Germany Read More Abegg, R. (1904). "Die Valenz und das periodische Syste