Chapter 11
Group 1: the alkali metals
Physical Properties
Halides, oxides, hydroxides
Salts of oxoacids
Aqueous solution chemistry including macrocyclic
complexes
Non-aqueous coordination chemistry
Li
1
Electrolysis cell used in the Downs process
2
http://www.crct.polymtl.ca/fact/Documentation/FTsalt/CaCl2-NaCl.jpg
Li2CO3
NaCl
Na2CO3
3
Occurrence of packing types assumed by elements
Body centered cubic is
not a close-packed structure
density g cm-3
0.53
0.97
0.86
1.53
1.90
4
Flame Test
Li
Na
Cs
Radioactive Dating
electron capture (proton
to neutron conversion)
40
19
40
18
Ar
K
b - decay
40
20
Ca
5
Reactivity of alkali metals with halogens, hydrogen, nitrogen
Alkali nitrides
Li3N

Na3N
 

 f H o ( MX , s )   a H o (M , s)  IE1 ( M , g )   a H o ( X , g )   EA ( X , g )   lattice H o (MX , s)
metal-dependant term
halide-dependant term
Standard enthalpies of formation (fH) and lattice
energies (latticeH) of alkali metal halides, MX.
6
Alkali oxides, hydroxides
Many nonmetals disproportionate
in aqueous alkali
suboxide Cs11O3
Solvay Process
7
Hydrogen bonding in solids
NaHCO3
KHCO3
In the solid state, hydrogen bonding results in anion
association in NaHCO3 and KHCO3
polyethers, cyclic polyethers, and crown ethers
complex alkali metal ions quite strongly
macrocyclic polyether
18-crown-6
[K(18-crown-6)]
crypt-[222]
[Na(crypt-[222])]Na
8
[Na2]2- dimer
Alkalides and Electrides
Electride
[Cs(crypt-222)2]+eelectron is trapped in a cavity of
of radius ~240 pm
crypt-222
9
Valinomycin
selective towards binding K+ ions.
Non-aqueous coordination chemistry
[{LiNHtBu}8]
10