Table 1
(continued)
Stoichiometry
Na
l B
m H
n O
(l+3m+n)/
2
Name
Synth T(K)
Space group
Unit cell
(Å or deg.)
X-ray T(K)
B-O (Å)
ranges
Comments
l
m
n
Tetrahedral
Trigonal
Refs.
104.38
1
3
0
α-sodium triborate
998
P21
̸ c
10.085,11.363,10.845
104.48
295
1.443–1.512
1.343–1.399
Spiro-B
5 O
6 and BO
4 [31]
β-sodium triborate
1003-1013
P21
̸ c
8.990,11.033,12.107
90.50
295
1.431–1.504
1.338–1.416
Spiro-B5O6, B3O3,
and BO
4 [32]
1
4
0
Sodium tetraborate
Melt
P21
̸ a
6.507,17.796,8.377
96.57
1.448–1.511
1.331–1.396
Spiro-B
5 O
6 and B
3 O
3 [33]
1
5
10
Sborgite
C2/c
11.119,16.474,13.576
112.83
1.456–1.482
1.339–1.412
[B5O6(OH)4]
−
ions [34]
1
5
4
Sodium pentaborate
423
P21
̸ c
8.701,8.067,12.977
106.77
1.451–1.489
1.342–1.394
[B
5 O
6 (OH)
4 ]
−
ions [35]
A Crystallographic Review of Alkali Borate Salts …
111