Inorganic Exam 3

inorganic complex

coordination compounds, structures with central metal atom/ion (Lewis acid) bonded to surrounding molecules or anions called ligands (Lewis bases) via coordinate covalent bonds

coordination compound

central metal with coordinated ions/compounds (ligands), overall neutral

coordination complex

complex ion and counter ion [coordination compound with charge] (anions or cations electrostatically attracted to complex ions)

coordination number (CN)

number of atoms bound to the metal center (4 and 6 most common

coordinative saturation

maximum coordination number (most d-block saturate at CN=6)

Lewis acid

e- pair acceptor, M or Mⁿ⁺ (neutral or cation metal)

Lewis base

e- pair donor, :L or :X^- (neutral or anionic)

denticity

number of pairs of e- a ligand shares with metal

monodentate

bites once, typically are single atoms (groups 5A, 6A, 7A)

Ex. fluoro (F^-), chloro (Cl^-), oxo (O^2-)

polydentate

bites multiple times, creates rings with the metal

Ex. ethylenediamine (en), oxalate (ox)

chelating

multidentate that encapsulates (claw)

Ex. ethylenediaminetetraacetic acid (EDTA)

bridging

atoms or compound bond to more than one metal center

ambidentate

directional or situational binding

empirical formula

rarest, least information, simplest ratio of elements, no structure information

Ex. CoN₅H₁₅Cl₃, CoCl₃*5NH₃, Co(NH₃)₃Cl₃

structural formula

coordination defined by square bracket for ions

Ex. [Co(NH₃)₅Cl]Cl₂

anionic ligands

end in -o

NO₂^-

nitro

ONO^-

nitrito

NO₃^-

nitrato

CO₃^2-

carbonato

C₂O₄^2-

oxalato

SO₃^2-

sulfito

SO₄^2-

sulfato

S₂O₃^2-

thiosulfate

ClO₃^-

chlorate

CH₃COO^-

acetato

OH^-

hydroxo

CN^-

cyano

NC^-

isocyano

SCN^-

thiocyanato

NCS^-

isothiocyanato

neutral ligands

are named as the neutral molecule

H₂O

aqua

NH₃

ammine

CO

carbonyl

NO

nitrosyl

large ligands (examples)

triphenylphosphine, triphenylarsine, ethylenediamine (en), acetylacetonato (acac)

use di, tri, tetra, etc

monatomic ligands (Cl^- = chloro)

“small” polyatomics (SO₄^2- = sulfato)

neutral (NH₃ = ammine)

cation counterion if complex is anionic (NH₄⁺ = ammonium)

use bis, tris, tetrakis, pentakis, hexakis, etc

already used another numerical prefix (ethylenediamine = en)

other “large” ligans with complex multi-word names

if metal complex is anion

use -ate suffix

Ag = argentate

Au = aurate

Pt = platinate

Fe = ferrate

Cu = cuprate

isomers

name number and types of atoms but different properties

stereoisomers

same number of atoms and bond types with different number of bonds (connectivity)

Ex. geometric and optical/enantiomer isomers

structural isomers

same number of atoms, different bond types/different number of bonds (connectivity)

Ex. ionization, coordination, linkage isomers

geometric isomers

different arrangement of ligands metal center

Ex. cis/trans [MA₂B₄] and fac/mer [MA₃B₃]

cis

same

trans

opposite

mer

meridian

fac

facial

enantiomer

non-superimposable structures, chemically indistinguishable expect in interaction with polarized light

ionization isomer

variation between an anion as coordinated ligand vs. counter-ion

[Co(NH₃)₅SO₄]NO₃ ←→ [Co(NH₃)₅NO₃]SO₄

coordination isomer

variation in ligation between 2 metal ions forming a neutral salt

[Co(en)₃]⁰[Cr(CN)₆]^-1 ←→ [Cr(en)₃]⁰[Co(CN)₆]⁰

linkage isomer

ambidentate ligand can bind using different atoms in different structures

18 electron rule

counting number of e- a metal experiences in its valence shell in complex, similar to octet rule for p-block elements, transition metal complexes most stable with 18 e- or even number of e-

carbonyl (CO)/carbonyl complex

neutral elemental metal coordinates to

crystal ligand field theory (CLFT)

bonding theory of coordination compounds, predict properties (magnetic behavior and color)