Geoscience Reference
In-Depth Information
Table 7.30 Experimental Conditions for the Growth of Li
4
B
7
O
12
Cl Crystals
[369]
No. Nutrient
Composition
Temperature
(
C)
Pressure
(bar)
%
Fill
Duration
(days)
Size
(mm)
Remarks
1
4
1.
Li
2
CO
3
—
1.000
250
90
60
8
Transparent cubic
crystals
B
2
O
3
—3.000
HCl (5 M)—
8ml
2.
Li
2
CO
3
—0.9
250
90
60
7
1
2
Transparent cubic
crystals
B
2
O
3
—3.000
HCl (5 M)—
8ml
3.
Li
2
CO
3
—0.8
250
90
58
7
1
2
Transparent cubic
crystals
B
2
O
3
—3.000
HCl (5 M)—
8ml
4.
Li
2
CO
3
—
1.000
250
90
60
8
0.5
1 Small transparent
cubic crystals
B
2
O
3
—3.000
HCl (5 M)—
8ml
5.
Li
2
CO
3
—1.2
250
90
60
8
0.5
1 Small transparent
cucic crystals
B
2
O
3
—3.000
HCl (5 M)—
8ml
6.
Li
2
CO
3
—
1.000
250
90
60
8
0.1
Very small
crystals
B
2
O
3
—3.000
The reaction of LiBO
2
and HCOOH resulted in the formation of HCOOLi.
When HCOOLi reacts with H
3
BO
3
with 1:3 ratio, Li
2
B
4
O
7
was formed but with an
increase in the amount of H
3
BO
3
(HCOOLi: H
3
BO
3
5
1:5) the new compound
LiH
2
B
5
O
9
has resulted.
The experimental conditions for the growth of LiH
2
B
5
O
9
are given in
Table 7.31
. During the crystallization process, hydrogen from HCOOH has entered
the structure indicating hydrolysis process. The crystals are colorless with vitreous
luster and pseudoorthorhombic symmetry
[356,365]
.
It is interesting to note that the growth of borates by hydrothermal method is not
yet popular, and even today the flux method followed by meet method are the most
popular ones. A large group of compounds with general formula RM
3
(BO
3
)
4
(where R
Al, Sc, Fe, Ga, Cr) have been obtained
mainly by flux method. However, the hydrothermal technique is slowly catching
up because of the advantages as listed earlier in the growth of Li
2
B
4
O
7
.
Applications of borates. Borates exhibit very interesting properties like piezo-
electric,
5
Y, La
Lu, Bi, In, but M
5
pyroelectric
and
ferroelectrics,
acousto-electric,
luminescent,
and
