Chapter 4 - Jacobs University

Chapter 9
Unpublished Results
9.1.6 Synthesis of K 7 Li 26 Mn 3 (H 2 O) 12
[Mn 4 (H 2 O) 16 (P 8 W 48 O 184 )(WO 4 ) 2 ]·55H 2 O(11a)
A sample of MnCl 2·6H 2 O (0.065 g, 0.33 mmol) was dissolved in 0.5 M LiCH 3 COO buffer
solution (20 mL) at pH 4.0 then K 28 Li 5 [H 7 P 8 W 48 O 184 ]·92H 2 O (0.187 g, 0.0125 mmol) was added.
Then 6-10 drops of 30% H 2 O 2 was added to that solution. The solution was heated to 80 °C for
1h and filtered hot and then the solution was layered with 1M NH 4 Cl solution. The filtrate was
allowed to evaporate in an open beaker at room temperature. After 2-3 days a green crystalline
product started to appear. After that, the evaporation was allowed to continue until the solution
level approached the solid product which was then collected by filtration and air dried. Yield:
0.120g (45%). IR: 1138(s), 1087(s), 1018(m), 982(sh), 930(sh), 920(sh), 800(s), 685(s), 572(w),
530(sh), 463 (w) cm -1 .
60
55
50
45
%Transmittance
40
35
30
25
20
15
1200
1100
1000
900
800
Wavenumbers (cm-1)
700
600
500
Figure 9.15 FT-IR spectrum of 11a.
158