Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo
Chemistry 2e

Key Terms

Chemistry 2eKey Terms

actinide series
(also, actinoid series) actinium and the elements in the second row or the f-block, atomic numbers 89–103
bidentate ligand
ligand that coordinates to one central metal through coordinate bonds from two different atoms
central metal
ion or atom to which one or more ligands is attached through coordinate covalent bonds
chelate
complex formed from a polydentate ligand attached to a central metal
chelating ligand
ligand that attaches to a central metal ion by bonds from two or more donor atoms
cis configuration
configuration of a geometrical isomer in which two similar groups are on the same side of an imaginary reference line on the molecule
coordination compound
stable compound in which the central metal atom or ion acts as a Lewis acid and accepts one or more pairs of electrons
coordination compound
substance consisting of atoms, molecules, or ions attached to a central atom through Lewis acid-base interactions
coordination number
number of coordinate covalent bonds to the central metal atom in a complex or the number of closest contacts to an atom in a crystalline form
coordination sphere
central metal atom or ion plus the attached ligands of a complex
crystal field splitting (Δoct)
difference in energy between the t2g and eg sets or t and e sets of orbitals
crystal field theory
model that explains the energies of the orbitals in transition metals in terms of electrostatic interactions with the ligands but does not include metal ligand bonding
d-block element
one of the elements in groups 3–11 with valence electrons in d orbitals
donor atom
atom in a ligand with a lone pair of electrons that forms a coordinate covalent bond to a central metal
eg orbitals
set of two d orbitals that are oriented on the Cartesian axes for coordination complexes; in octahedral complexes, they are higher in energy than the t2g orbitals
f-block element
(also, inner transition element) one of the elements with atomic numbers 58–71 or 90–103 that have valence electrons in f orbitals; they are frequently shown offset below the periodic table
first transition series
transition elements in the fourth period of the periodic table (first row of the d-block), atomic numbers 21–29
fourth transition series
transition elements in the seventh period of the periodic table (fourth row of the d-block), atomic numbers 89 and 104–111
geometric isomers
isomers that differ in the way in which atoms are oriented in space relative to each other, leading to different physical and chemical properties
high-spin complex
complex in which the electrons maximize the total electron spin by singly populating all of the orbitals before pairing two electrons into the lower-energy orbitals
hydrometallurgy
process in which a metal is separated from a mixture by first converting it into soluble ions, extracting the ions, and then reducing the ions to precipitate the pure metal
ionization isomer
(or coordination isomer) isomer in which an anionic ligand is replaced by the counter ion in the inner coordination sphere
lanthanide series
(also, lanthanoid series) lanthanum and the elements in the first row or the f-block, atomic numbers 57–71
ligand
ion or neutral molecule attached to the central metal ion in a coordination compound
linkage isomer
coordination compound that possesses a ligand that can bind to the transition metal in two different ways (CN vs. NC)
low-spin complex
complex in which the electrons minimize the total electron spin by pairing in the lower-energy orbitals before populating the higher-energy orbitals
monodentate
ligand that attaches to a central metal through just one coordinate covalent bond
optical isomer
(also, enantiomer) molecule that is a nonsuperimposable mirror image with identical chemical and physical properties, except when it reacts with other optical isomers
pairing energy (P)
energy required to place two electrons with opposite spins into a single orbital
platinum metals
group of six transition metals consisting of ruthenium, osmium, rhodium, iridium, palladium, and platinum that tend to occur in the same minerals and demonstrate similar chemical properties
polydentate ligand
ligand that is attached to a central metal ion by bonds from two or more donor atoms, named with prefixes specifying how many donors are present (e.g., hexadentate = six coordinate bonds formed)
rare earth element
collection of 17 elements including the lanthanides, scandium, and yttrium that often occur together and have similar chemical properties, making separation difficult
second transition series
transition elements in the fifth period of the periodic table (second row of the d-block), atomic numbers 39–47
smelting
process of extracting a pure metal from a molten ore
spectrochemical series
ranking of ligands according to the magnitude of the crystal field splitting they induce
steel
material made from iron by removing impurities in the iron and adding substances that produce alloys with properties suitable for specific uses
strong-field ligand
ligand that causes larger crystal field splittings
superconductor
material that conducts electricity with no resistance
t2g orbitals
set of three d orbitals aligned between the Cartesian axes for coordination complexes; in octahedral complexes, they are lowered in energy compared to the eg orbitals according to CFT
third transition series
transition elements in the sixth period of the periodic table (third row of the d-block), atomic numbers 57 and 72–79
trans configuration
configuration of a geometrical isomer in which two similar groups are on opposite sides of an imaginary reference line on the molecule
weak-field ligand
ligand that causes small crystal field splittings
Order a print copy

As an Amazon Associate we earn from qualifying purchases.

Citation/Attribution

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at https://openstax.org/books/chemistry-2e/pages/1-introduction
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/chemistry-2e/pages/1-introduction
Citation information

© Jan 8, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.