Water Quality
Ambient Water Quality Criteria for Fluoride
Table 2.1 Percentage of Fluorine by Weight in some Fluoride Salts and their Solubility in Water at 0 to 25° C (Weast, 1968)
Formula
Molecular Weight
Fluoride %
Solubility in Water (0 to 25°C ) : mg/L
BaF2
175.3
21.7
1 200
BaSiF6
279.4
40.8
260
CaF2
78.1
48.7
16
CaSiF6
182.2
62.6
slight
HF
20.0
95.0
soluble*
KF
58.1
32.7
923 000
K2SiF6
220.3
51.7
KF:HF
410 000
LiF
25.9
73.4
2 700
LiSiF6 2H2O
169.0
67.5
730 000
MgF2
62.3
44.9
76
MgSiF6
166.4
68.5
650 000
MnF2
92.9
40.9
6 600
NaF
42.0
45.2
42 200
Na2SiF6
188.1
60.6
6 520
Na3AlF6
210.0
54.3
__
NaF:HF
62.0
61.3
NH4F
37.0
51.4
1 000
(NH4)2SiF6
178.1
64.0
186 000
NH4F:HF
57.0
66.7
SrF2
125.6
30.3
117
* Soluble means virtually unlimited solubility.
