A molecular orbital (MO) diagram is a graphical representation of the molecular orbitals in a molecule. It is used to visualize how atomic orbitals combine to form molecular orbitals when atoms come together to form molecules. The key aspects of molecular orbital diagrams include: 1. **Atomic Orbitals**: The starting point for constructing an MO diagram involves identifying the atomic orbitals of the individual atoms that will combine. Common atomic orbitals include s, p, d, and f orbitals.
Pi backbonding, often referred to in the context of chemistry, particularly in coordination chemistry and organometallic chemistry, is a type of bonding interaction between a metal center and a ligand. It typically involves the donation of electron density from a filled metal d-orbital to an empty orbital of a ligand, usually a π* (pi-star) orbital, which is the antibonding orbital associated with pi bonds.
A pyramidal alkene doesn't exist as a distinct category in traditional organic chemistry. However, the term might refer to alkenes that possess a certain spatial arrangement or stereochemistry. In organic chemistry, alkenes are compounds that contain at least one carbon-carbon double bond (C=C). They are typically characterized by a planar geometry around the double bond due to the sp² hybridization of the carbon atoms involved in the double bond, leading to a trigonal planar configuration.
Sigma-pi and equivalent-orbital models are concepts from molecular and solid-state physics that deal with the electronic structure of molecules and materials. ### Sigma-Pi Models 1. **Sigma Bonds (σ Bonds)**: These are covalent bonds formed when two atoms share electrons in an overlapping region of their atomic orbitals along the axis connecting the two nuclei. Sigma bonds are generally stronger because they involve direct overlap.
A triple bond is a type of chemical bond that involves the sharing of three pairs of electrons between two atoms. This bond is stronger than a single bond (which shares one pair of electrons) and a double bond (which shares two pairs of electrons). In a triple bond, the two atoms involved each contribute three electrons, resulting in a total of six electrons being shared.
Git tips by Ciro Santilli 37 Updated 2025-07-16
This is a quick presentation that goes over some of the most common difficulties people find with Git.
Other Bitcon analysis:
It is unbelievable that you can't find easily on YouTube recreations of many of the key physics/chemistry experiments and of common laboratory techniques.
Experiments, the techniques required to to them, and the history of how they were first achieved, are the heart of the natural sciences. Without them, there is no motivation, no beauty, no nothing.
School gives too much emphasis on the formulas. This is bad. Much more important is to understand how the experiments are done in greater detail.
The videos must be completely reproducible, indicating the exact model of every experimental element used, and how the experiment is setup.
A bit like what Ciro Santilli does in his Stack Overflow contributions but with computers, by indicating precise versions of his operating system, software stack, and hardware whenever they may matter.
It is understandable that some experiments are just to complex and expensive to re-create. As an extreme example, say, a precise description of the Large Hadron Collider anyone? But experiments up to the mid-20th century before "big science"? We should have all of those nailed down.
We should strive to achieve the cheapest most reproducible setup possible with currently available materials: recreating the original historic setup is cute, but not a priority.
Furthermore, it is also desirable to reproduce the original setups whenever possible in addition to having the most convenient modern setup.
This project is to a large extent a political endeavour.
Someone with enough access to labs has to step up and make a name for themselves through the huge effort of creating a baseline of amazing content without yet being famous.
Until it reaches a point that this person is actively sought to create new material for others, and things snowball out of control. Maybe, if the Gods allow it, that person could be Ciro.
Tutorials with a gazillion photos and short videos are also equally good or even better than videos, see for example Ciro's How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in bacteria for an example that goes toward that level of perfection.
The Applied Science does well in that direction.
This project is one step that could be taken towards improving the replication crisis of science. It's a bit what Hackster.io wants to do really. But that website is useless, just use OurBigBook.com and create videos instead :-)
We're maintaining a list of experiments for which we could not find decent videos at: Section "Physics experiment without a decent modern video".
Ciro Santilli visited the teaching labs of a large European university in the early 2020's. They had a few large rooms filled with mostly ready to run versions of several key experiments, many/most from "modern physics", e.g. Stern-Gerlach experiment, Quantum Hall effect, etc.. These included booklets with detailed descriptions of how to operate the apparatus, what you'd expect to see, and the theory behind them. With a fat copyright notice at the bottom. If only such universities aimed to actually serve the public for free rather than hoarding resources to get more tuition fees, university level education would already have been solved a long time ago!
One thing we can more or less easily do is to search for existing freely licensed videos and add them to the corresponding Wikipedia page where missing. This requires knowing how to search for freely licensed videos:
A (multi-user) blog is the hello world of the web, so creating one of those is the best way to quickly evaluate web technology, i.e. time to Hello World.
Some new frameworks like FeathersJS are making a chat app instead, as that highlights the push notifications a bit better.
This program did not have certain dynamic linking related sections because we linked it minimally with ld.
However, if you compile a C hello world with GCC 8.2:
gcc -o main.out main.c
some other interesting sections would appear.
Chomp is a two-player mathematical strategy game played on a rectangular grid of squares, representing chocolate bars. The game mechanics are straightforward: players take turns selecting a square, and when a player picks a square, all squares to the right and below it are "chomped" or removed from the game. Here's how it works: 1. The game starts with a chocolate bar represented by a grid of squares.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact