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19.5: Key Terms

  • Page ID
    452610
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    Example and Directions
    Words (or words that have the same definition)The definition is case sensitive(Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages](Optional) Caption for Image(Optional) External or Internal Link(Optional) Source for Definition
    (Eg. "Genetic, Hereditary, DNA ...")(Eg. "Relating to genes or heredity")The infamous double helix https://bio.libretexts.org/CC-BY-SA; Delmar Larsen
    Glossary Entries
    Word(s)DefinitionImageCaptionLinkSource
    actinide series(also, actinoid series) actinium and the elements in the second row or the f-block, atomic numbers 89–103    
    bidentate ligandligand that coordinates to one central metal through coordinate bonds from two different atoms    
    central metalion or atom to which one or more ligands is attached through coordinate covalent bonds    
    chelatecomplex formed from a polydentate ligand attached to a central metal    
    chelating ligandligand that attaches to a central metal ion by bonds from two or more donor atoms    
    cis configurationconfiguration of a geometrical isomer in which two similar groups are on the same side of an imaginary reference line on the molecule    
    coordination compoundstable compound in which the central metal atom or ion acts as a Lewis acid and accepts one or more pairs of electrons    
    coordination compoundsubstance consisting of atoms, molecules, or ions attached to a central atom through Lewis acid-base interactions    
    coordination numbernumber 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 spherecentral 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 theorymodel 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 elementone of the elements in groups 3–11 with valence electrons in d orbitals    
    donor atomatom in a ligand with a lone pair of electrons that forms a coordinate covalent bond to a central metal    
    eg orbitalsset 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 seriestransition elements in the fourth period of the periodic table (first row of the d-block), atomic numbers 21–29    
    fourth transition seriestransition elements in the seventh period of the periodic table (fourth row of the d-block), atomic numbers 89 and 104–111    
    geometric isomersisomers 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 complexcomplex 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    
    hydrometallurgyprocess 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    
    ligandion or neutral molecule attached to the central metal ion in a coordination compound    
    linkage isomercoordination compound that possesses a ligand that can bind to the transition metal in two different ways (CN vs. NC)    
    low-spin complexcomplex in which the electrons minimize the total electron spin by pairing in the lower-energy orbitals before populating the higher-energy orbitals    
    monodentateligand 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 metalsgroup 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 ligandligand 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 elementcollection of 17 elements including the lanthanides, scandium, and yttrium that often occur together and have similar chemical properties, making separation difficult    
    second transition seriestransition elements in the fifth period of the periodic table (second row of the d-block), atomic numbers 39–47    
    smeltingprocess of extracting a pure metal from a molten ore    
    spectrochemical seriesranking of ligands according to the magnitude of the crystal field splitting they induce    
    steelmaterial made from iron by removing impurities in the iron and adding substances that produce alloys with properties suitable for specific uses    
    strong-field ligandligand that causes larger crystal field splittings    
    superconductormaterial that conducts electricity with no resistance    
    t2g orbitalsset 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 seriestransition elements in the sixth period of the periodic table (third row of the d-block), atomic numbers 57 and 72–79    
    trans configurationconfiguration of a geometrical isomer in which two similar groups are on opposite sides of an imaginary reference line on the molecule    
    weak-field ligandligand that causes small crystal field splittings    

    19.5: Key Terms is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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