Table 1
Crystal structures of boron oxide and boric acid
Stoichiometry
B
m H
n O
(3m+n)/2
Name
Synth
T(K)
Space
group
Unit cell
(Å or deg.)
X-ray
T(K)
B-O (Å) ranges
Comments
m
n
Tetrahedral
Trigonal
References
1
0
Boron oxide-I
513
C3 1
4.334, 8.334
1.31–2.145
n/a
Powder, BO
4
tetrahedra [13]
P3 1
4.33, 8.39
293
n/a
1.38
Powder XRD and
ED, BO
3 [14]
573
P3 1
4.336,8.340
n/a
1.336–1.404
Chain of BO
3 [15]
P3 1 21
4.3358,8.3397
n/a
1.356–1.375
[16]
Boron oxide-II
1373
65 kb
Ccm2 1
4.613,
7.803,4.129
1.373-1.512
n/a
BO
4 tetrahedra
[17]
1
3
Orthoboric acid
(sassolite)
P1
7.04,7.04,6.56
92.50,
101.16,120.0
n/a
1.36
Assumed H in
middle of Os [18]
1.36
Electron diff.,
small xtal [19]
P1
7.039,
7.053,6.578,
92.58,101.17,
119.83
298
n/a
1.353–1.365
AB stacked layers
[20]
Orthoboric
acid-T
298
P3 2
7.0453,9.5608
297
n/a
1.349–1.377
ABC stacked
layers [21]
1
1
Metaboric acid
(orthorhombic
α)
423
Pnma or
Pa
8.015,9.679,
6.244
n/a
1.37
[22, 23]
443
Pbnm
8.019,
9.703,6.13
143
n/a
1.347–1.391
B
3 O
3 (OH)
3 layers
[24]
Metaboric acid
(monoclinic
β)
433
P2 1
̸ c
6.76,8.80,7.15
92.67
[22]
P2 1
̸ a
7.132,8.852,
6.772
93.253
1.42–1.51
1.29–1.41
[25]
P2 1
̸ a
7.122,8.842,
6.771 93.26
1.433–1.553
1.345–1.386
B
3 O
4 (OH)(OH
2 )
chains [26]
(continued)
An Ab Initio Study of Boric Acid, Borate …
145
Crystal structures of boron oxide and boric acid
Stoichiometry
B
m H
n O
(3m+n)/2
Name
Synth
T(K)
Space
group
Unit cell
(Å or deg.)
X-ray
T(K)
B-O (Å) ranges
Comments
m
n
Tetrahedral
Trigonal
References
1
0
Boron oxide-I
513
C3 1
4.334, 8.334
1.31–2.145
n/a
Powder, BO
4
tetrahedra [13]
P3 1
4.33, 8.39
293
n/a
1.38
Powder XRD and
ED, BO
3 [14]
573
P3 1
4.336,8.340
n/a
1.336–1.404
Chain of BO
3 [15]
P3 1 21
4.3358,8.3397
n/a
1.356–1.375
[16]
Boron oxide-II
1373
65 kb
Ccm2 1
4.613,
7.803,4.129
1.373-1.512
n/a
BO
4 tetrahedra
[17]
1
3
Orthoboric acid
(sassolite)
P1
7.04,7.04,6.56
92.50,
101.16,120.0
n/a
1.36
Assumed H in
middle of Os [18]
1.36
Electron diff.,
small xtal [19]
P1
7.039,
7.053,6.578,
92.58,101.17,
119.83
298
n/a
1.353–1.365
AB stacked layers
[20]
Orthoboric
acid-T
298
P3 2
7.0453,9.5608
297
n/a
1.349–1.377
ABC stacked
layers [21]
1
1
Metaboric acid
(orthorhombic
α)
423
Pnma or
Pa
8.015,9.679,
6.244
n/a
1.37
[22, 23]
443
Pbnm
8.019,
9.703,6.13
143
n/a
1.347–1.391
B
3 O
3 (OH)
3 layers
[24]
Metaboric acid
(monoclinic
β)
433
P2 1
̸ c
6.76,8.80,7.15
92.67
[22]
P2 1
̸ a
7.132,8.852,
6.772
93.253
1.42–1.51
1.29–1.41
[25]
P2 1
̸ a
7.122,8.842,
6.771 93.26
1.433–1.553
1.345–1.386
B
3 O
4 (OH)(OH
2 )
chains [26]
(continued)
An Ab Initio Study of Boric Acid, Borate …
145