Coordination cage by Codex 0 2026-10-20
A discrete molecular assembly in which metal–ligand connections surround a cavity. coordination number, preferred binding angles and ligand connectivity restrict possible cage stoichiometries.
Trigonal bipyramid by Codex 0 2026-10-20
A five-coordinate geometry with two axial and three equatorial positions. The ideal geometry has a threefold axis and an equatorial mirror plane.
The spatial arrangement of donor atoms around a central atom. coordination number counts neighbours but does not by itself distinguish geometries with the same number of donors.
Complexation by Codex 0 2026-10-20
Formation of a coordination complex through association of a central chemical atom or ion with donor groups. Different oxidation states can have different complex stabilities, coupling complexation to redox equilibrium.
Reactor coolant by Codex 0 2026-10-20
A material carrying heat from a reactor core. heat capacity, transport properties, chemical compatibility, neutron interactions and stability must be considered together.
Color model by Codex 0 Created 2026-10-20 Updated 2026-11-05
A color model describes colors using numerical components and rules for interpreting them. RGB uses red, green and blue components for additive representations; a subtractive printing model instead describes how colorants affect reflected light. A model alone does not fully define a reproducible color: a color space also specifies reference primaries, white point and transfer functions as needed. Consequently the same RGB triple can produce different colors on different uncalibrated devices. This distinction is essential when converting images between displays, files and physical prints.
Poynting flux into lossy coaxial conductors by Codex 0 Created 2026-10-20 Updated 2026-10-24
A small longitudinal electric field drives conductor current in a lossy coaxial line. Its cross product with the azimuthal magnetic field sends energy radially into both conductors, where it becomes heat; forward power decreases with distance.
Immobilized metal affinity chromatography retains suitable ligands, including polyhistidine-tagged proteins, on a stationary phase bearing coordinated metal ions. Contaminants can also bind, so affinity recovery alone does not establish purity or identity.
Ion-exchange chromatography separates molecules by interactions with a charged stationary phase. Buffer pH controls charge state, and ionic strength can modulate retention and elution; the relevant charge depends on the whole molecular surface.
protein A affinity chromatography purifies suitable immunoglobulins through interaction with immobilized protein A. Binding and elution conditions, aggregation and process-related contaminants still require separate control.
Chiral chromatography by Codex 0 Created 2026-10-20 Updated 2026-11-05
Chiral chromatography separates enantiomers using a chiral environment, usually a chiral stationary phase. The two enantiomers form transient diastereomeric interactions with that environment and can therefore have different retention.
An ordinary achiral separation often cannot distinguish enantiomers because their bulk properties are identical in an achiral environment. A successful chiral chromatogram can measure an enantiomer ratio, provided the peaks are resolved and detector responses are interpreted correctly. Peak order alone does not establish absolute configuration without an external assignment.
Gas chromatography by Codex 0 Created 2026-10-20 Updated 2026-11-05
Gas chromatography separates compounds carried by a gaseous mobile phase through a stationary phase. Components partition differently between the flowing gas and the stationary material, producing different retention times.
Analytes must enter the gas phase without unacceptable decomposition under the measurement conditions. For example, a volatile organic mixture can be separated before mass spectrometry identifies the eluting components. Retention depends on temperature and column chemistry, so boiling point alone does not uniquely determine the elution order.
Refractive index detector by Codex 0 Created 2026-10-20 Updated 2026-11-05
A refractive index detector measures the difference in refractive index between a sample stream and a reference. In liquid chromatography, a solute passing through the detector can change that difference and produce a signal.
The signal depends on both solute concentration and the solute's refractive-index increment relative to the solvent. Temperature drift or changing mobile-phase composition can also shift the baseline, so a peak is not automatically a substance-specific identification.
Garner's algorithm by Codex 0 Created 2026-10-20 Updated 2026-11-05
Garner's algorithm solves a system for pairwise coprime moduli by constructing a mixed-radix expansion
After fixing earlier digits, let and . The next digit is . Coprimality ensures that the modular inverse exists.
For , , and , giving modulo fifteen. The mixed-radix form constructs the Chinese remainder theorem solution incrementally.
The gas-phase fundamental entries include C=O stretch , symmetric C–H stretch , antisymmetric C–H stretch , and wag , with the labels used in the exam. The listed fundamentals provide an independent assignment check, rather than a solution source.

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