Transition Metals & Coordination Compounds
Chapter 24Transition Metals &Coordination Compounds24.2
Properties of Transition MetalsReview Electron ConfigurationTrends
in the Periodic Table24.3 Coordination Compounds The BasicsExample
of Naming24.4 Structure and Isomerization
Transition Metals contain e- in d Orbitals
http://www.can-do.com/uci/lessons98/Periodic.htmlhttp://www.can-do.com/uci/lessons98/Periodic.htmlBreath
slow down!2Why Are Transition Metals & Coordination Compounds
Important?Therapeutic drugsChemical SensorsColoring agents
PaintsCosmeticsBiological MoleculesHemeglobinChlorophyllGems
(Jewelry & Technological Applications)Rubies, Emeralds,
Garnets, etc.Lasers
24.2 Properties of Transition MetalsModerate to High
DensitiesGood Electrical ConductivityHigh Melting PointsModerate to
Extreme Hardness
http://www.tutorvista.com/chemistry/shapes-of-d-orbitalsDue to
the delocalization of d electrons in metallic bondingExceptions:
Elements with filled d orbitals, which prevents d-d bonding. Hg has
a low melting point and is liquid at room temperature.
Electron Configuration
Increasing Energy(n-1)d(n-2)fElectron Configuration
[noble gas] ns2 (n-1)dx
[noble gas] ns2 (n-2)f14 (n-1)dx Slow down - Breath6Electron
Configuration
[Kr]5s24d2http://malaxoschemistry.wikispaces.com/Periodic+TableAtomic
Size
Decreasing SizeIncreasIng
S izehttp://malaxoschemistry.wikispaces.com/Periodic+TableAtomic
Size
Exception to the trend: Electrons in the f-orbitals are not
effective at shielding outer shell electrons from nuclear charge.
So, the outer electrons are held in close this is known as
lanthanide contraction.Keep it simple! breath9Ionization Energy
IncreasesDecreaseshttp://malaxoschemistry.wikispaces.com/Periodic+Table
Ionization EnergyException to the trend: Note that 5d elements
have a greater ionization energy. This is again due to outer shell
electron being held closer to the nucleus, so it take more energy
to pull them away. Electronegativity
http://malaxoschemistry.wikispaces.com/Periodic+TableIncreasesDecreases
ElectronegativityException to the trend: There is an increase in
electronegativity from the 3d (1st row transition metals) to the 4d
(2nd row transition metals). Au: EN = 2.4Compared to P: EN = 2.1
!!Gold breath slow down13Oxidation States
In general, stability is found in full or half-full shells, and
in a configuration that looks like a noble gas.Scandium1424.3
Coordination CompoundsComplex Ion - Central Metal bound to one or
more ligandsLigands are Lewis Base* (electron donors) and can be
either neutral or negatively chargedThe charge on the complex ion
is balance by counter ions of opposite charge
The combination of a complex ion and counter ions results in a
coordination compoundDavid N. Blauch -
http://www.chm.davidson.edu/vce/index.htm
*Corrected 4/15/11 @ 2:30 pm)A Little BackgroundIn 1893, Swiss
chemist Alfred Werner came up with the idea that a central metal
could have 2 types of interactionsPrimary Valence Oxidation State
of the central metalSecondary Valence Number of molecules or ions
directly attached to the central metal or Coordination Number
Example: [Co(NH3)6]Cl3The Primary Valence or Oxidation State of
Co is +3The Secondary Valence or Coordination Number is 6 (6
ammonia ligands are directly attached to Co
Other cobalt(III) coordination
compounds[Co(NH3)6]Cl3[Co(NH3)5Cl]Cl2[Co(NH3)4Cl2]ClCoordinate
Covalent BondsLewis Acid-Base Adduct the ligand donates its
electrons to the empty metal orbitals to form a coordinate covalent
bond
Lewis AcidLewis BaseML:AdductSome Common Ligands
Chelating AgentsLigands can have one or more bonding pairs of
electronsMonodentateBidentate or Polydentate
Complex ions with bidentate or polydentate ligands are chelates,
and the coordinating ligands are chelating agents
EDTA is
hexadentatehttp://library.kiwix.org:4201/A/Inorganic_chemistry.htm
CoGeometries
Anne Marie Helmenstine, Ph.D., About.com Guide
Naming Coordination Compounds[Mn(CO)(NH3)5]SO4 (neutral ligands
are written before charged ligands in the formula)Cation 1stName
the ligands in alphabetical orderamminecarbonylAdd a prefix to
indicate the number of ligandspentaammineName the metal ion
Manganese(II)Anion 2ndSulfatePentaamminecarbonylmanganese(II)
sulfate24.4 Structure & IsomerismSame formula different
structuresDifferent connectivitiesSame connectivities different
spacial arrangementsLigands & counter ions trade placesLigands
coordinate in different waysDifferent spacial arrangementsMirror
imagesStructural IsomersCoordination Isomers
David N. Blauch -
http://www.chm.davidson.edu/vce/index.htmpentaamminesulfatochromium(III)
bromidepentaamminebromochromium(III) sulfateStructural
IsomersLinkage Isomers
David N. Blauch -
http://www.chm.davidson.edu/vce/index.htmpentaamminenitrocobalt(III)
ionpentaamminenitritocobalt(III) ionStereoisomersGeometric Isomers:
cis-trans
cistransDavid N. Blauch -
http://www.chm.davidson.edu/vce/index.htmcis-diamminedichloroplatinum(II)trans-diamminedichloroplatinum(II)StereoisomersGeometric
Isomers: fac-merfacmer
David N. Blauch -
http://www.chm.davidson.edu/vce/index.htmfac-triamminetrichlorocobalt(III)mer-triamminetrichlorocobalt(III)StereoisomersOptical
IsomersMirror ImagesNon-superimposableEnantimomersChiral: optically
active (rotates polarized light)
http://www.wikidoc.org/index.php/Chirality_%28chemistry%29
http://en.wikipedia.org/wiki/Chirality_%28electromagnetism%29ChiralityDetermining
Optical Activity
facmerDavid N. Blauch -
http://www.chm.davidson.edu/vce/index.htmChiralityDetermining
Optical Activity
Superimposable - No optical activity