Transition Metals and Coordination Chemistry

Vocabulary

actinide series

f-block elements in period 7 of the periodic table, which consists of elements actinium (Ac) through lawrencium (Lr)

bidentate ligand

ligand in a coordination complex that donates two pairs of electrons to the central metal atom or ion

chelate

coordination complex formed between a central metal atom or ion and chelating ligands, which are ions or molecules that bond to it with more than one atom

cis configuration

geometric arrangement in which two identical substituents are on the same side of the central part of a molecule or an ion

coordination complex

central metal atom or ion surrounded by ligands, as well as bonded ions if the central part has an overall charge

coordination number

number of atoms bound to the single central metal center in a coordination complex

coordination sphere

part of a coordination complex consisting of the central metal atom or ion and all ligands surrounding it

crystal field splitting energy

energy difference between the higher energy $e_g$ (${d_{{z^2}}}$and ${d_{{x^2}-{y^2}}}$) and lower energy $t_{2g}$ (${d_{xy}}$, ${d_{yz}}$, and ${d_{xz}}$) symmetric orbitals

crystal field theory

electrostatic model that is used to describe and predict energy differences between nd orbital sets in transition metal complexes

d-block element

element with one or more valence electrons in a d orbital

f-block element

element with 4f or 5f electrons in its valence shell

geometric isomer

one of two or more molecules that have the same molecular formula and bond structure but differ in the positions of substituents around a rigid part of the molecule

high-spin complexes

complex in which electrons fill higher orbitals singly and the pairing energy is large relative to the crystal field splitting energy

ionization isomer

one of two forms of a coordination complex that differ only in which of two species is a ligand and which is outside the coordination sphere

isomer

one of two or more molecules that share the same chemical formula but have different arrangements of atoms

lanthanide series

f-block elements in period 6 of the periodic table, which consists of elements lanthanum (La) to lutetium (Lu)

ligand

ion or molecule that bonds to a central metal atom or ion as part of a coordination complex

one of two or more coordination complexes that differ in how a ligand is bonded to the central metal atom or ion

low-spin complexes

complex in which electrons preferentially pair in lower-energy orbitals and the pairing energy is small relative to the crystal field splitting energy

monodentate ligand

ligand in a coordination complex that donates a single pair of electrons to the central metal atom or ion

optical isomer

one of a pair of mirror-image molecules that are not identical and cannot be superimposed

pairing energy (P)

energy required for two electrons to occupy a single orbital

polydentate ligand

ligand in a coordination complex that donates three or more pairs of electrons to the central metal atom or ion

rare earth element

one of 15 lanthanides and 2 transition metals that have similar chemical properties and are commonly found together in nature

smelting

technique by which an elemental metal is extracted from its ore through heating and melting

spectrochemical series

list of ligands ordered according to their ability to induce crystal field splitting for a common metal center

superconductor

material that can conduct electric current with almost zero resistance when cooled to appropriate temperatures

trans configuration

geometric arrangement in which two identical substituents are on opposite sides of the central part of a molecule or an ion

transition metal

element in groups 3 through 12 of the periodic table