Table 4
Crystal structures of Rubidium Borates
Stoichiometry
Rb
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.
3
3
8
Pna2
1
7.90,13.95,9.28
1.44–1.50
1.37–1.45
[B
3 O
4 (OH)
4 ]
3−
ions [75]
1
1
0
R3̄ c
13.21, 7.78
[37]
Rubidium
metaborate
1173
R3̄ c
13.1572,7.7434
293
1.315–1.407
[B
3 O
6 ]
3−
ions [76]
1
2
5.6
298
Pbcn
11.276,13.097,16.751
298
1.416–1.524
1.352–1.391
[B
4 O
5 (OH)
4 ]
2−
ions [77]
1
2
0
980
P1̄
9.860,10.653,6.649,
103.4,101.4,89.1
1.41–1.50
1.33–1.40
B
4 O
5 , B
3 O
3 and BO
3
units [78]
3
7
0
913
P1̄
6.603,6.632,30.085,
91.183,91.781,119.293
1.42–1.53
1.31–1.41
B
5 O
6 , B
3 O
3 and BO
4
units [79]
1
3
0
α-rubidium
triborate
873
P212121
8.209,10.092,5.382
1.44–1.58
1.31–1.40
powder XRD, B
3 O
3
units [80]
β-rubidium
triborate
973
P2
1 2
1 2
1
8.438,8.719,6.240
293
1.45–1.49
1.34–1.40
B
3 O
3 units [81]
2
7
5
443
P2
1
̸ n
8.047,11.785,13.952,
102.974
298
1.420–1.500
1.333–1.395
[B
7 O
9 (OH)
5 ]
2−
ions [82]
1
5
8
298
Aea2
11.302,10.962,9.335
298
1.473–1.474
1.344–1.375
[B
5 O
6 (OH)
4 ]
−
ions [83]
1
5
0
β-rubidium
pentaborate
973
Pbca
7.50, 11.84, 14.80
B
5 O
6 units [55]
1003
Pbca
7.553, 11.857, 14.813
298
1.464–1.481
1.339–1.391
[84]
A Crystallographic Review of Alkali Borate Salts …
117
Crystal structures of Rubidium Borates
Stoichiometry
Rb
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.
3
3
8
Pna2
1
7.90,13.95,9.28
1.44–1.50
1.37–1.45
[B
3 O
4 (OH)
4 ]
3−
ions [75]
1
1
0
R3̄ c
13.21, 7.78
[37]
Rubidium
metaborate
1173
R3̄ c
13.1572,7.7434
293
1.315–1.407
[B
3 O
6 ]
3−
ions [76]
1
2
5.6
298
Pbcn
11.276,13.097,16.751
298
1.416–1.524
1.352–1.391
[B
4 O
5 (OH)
4 ]
2−
ions [77]
1
2
0
980
P1̄
9.860,10.653,6.649,
103.4,101.4,89.1
1.41–1.50
1.33–1.40
B
4 O
5 , B
3 O
3 and BO
3
units [78]
3
7
0
913
P1̄
6.603,6.632,30.085,
91.183,91.781,119.293
1.42–1.53
1.31–1.41
B
5 O
6 , B
3 O
3 and BO
4
units [79]
1
3
0
α-rubidium
triborate
873
P212121
8.209,10.092,5.382
1.44–1.58
1.31–1.40
powder XRD, B
3 O
3
units [80]
β-rubidium
triborate
973
P2
1 2
1 2
1
8.438,8.719,6.240
293
1.45–1.49
1.34–1.40
B
3 O
3 units [81]
2
7
5
443
P2
1
̸ n
8.047,11.785,13.952,
102.974
298
1.420–1.500
1.333–1.395
[B
7 O
9 (OH)
5 ]
2−
ions [82]
1
5
8
298
Aea2
11.302,10.962,9.335
298
1.473–1.474
1.344–1.375
[B
5 O
6 (OH)
4 ]
−
ions [83]
1
5
0
β-rubidium
pentaborate
973
Pbca
7.50, 11.84, 14.80
B
5 O
6 units [55]
1003
Pbca
7.553, 11.857, 14.813
298
1.464–1.481
1.339–1.391
[84]
A Crystallographic Review of Alkali Borate Salts …
117