Selenic acid
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| Names | |||
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IUPAC name
Selenic(VI) acid
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| Other names
Selenic acid
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| Identifiers | |||
7783-08-6 
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| 3D model (Jmol) | Interactive image | ||
| ChEBI |
CHEBI:18170 
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| ChemSpider |
1058
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| ECHA InfoCard | 100.029.072 | ||
| KEGG |
C05697
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| PubChem | 1089 | ||
| RTECS number | VS6575000 | ||
| UNII |
HV0Y51NC4J
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| Properties | |||
| H 2SeO 4 |
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| Molar mass | 144.9734 g/mol | ||
| Appearance | Colorless deliquescent crystals | ||
| Density | 2.95 g/cm3, solid | ||
| Melting point | 58 °C (136 °F; 331 K) | ||
| Boiling point | 260 °C (500 °F; 533 K) (decomposes) | ||
| 130 g/100 mL (30 °C) | |||
| Acidity (pKa) | -3, 1.9 | ||
| −51.2·10−6 cm3/mol | |||
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Refractive index (nD)
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1.5174 (D-line, 20 °C) | ||
| Structure | |||
| tetrahedral at Se | |||
| Hazards | |||
| Main hazards | Corrosive, highly toxic | ||
| R-phrases | 23/25-33-50/53 | ||
| S-phrases | 20/21-28-45-60-61 | ||
| NFPA 704 | |||
| Related compounds | |||
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Other anions
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selenious acid hydrogen selenide |
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Other cations
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sodium selenate | ||
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Related compounds
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Sulfuric acid Selenium dioxide Selenium trioxide Telluric acid |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is ?) |
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| Infobox references | |||
Selenic acid is the inorganic compound with the formula H
2SeO
4. It is an oxoacid of selenium, and its structure is more accurately described as (HO)
2SeO
2. It is a colorless compound. Although it has few uses, its derivative sodium selenate is used in the production of glass and animal feeds.
The molecule is tetrahedral, as predicted by VSEPR theory. The a Se–O bond length is 161 pm. In the solid state, it crystallizes in an orthorhombic structure.
It is prepared by oxidising selenium compounds in lower oxidation states. One method involves the oxidation of selenium dioxide with hydrogen peroxide:
Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method. Instead, selenic acid may also be prepared by the oxidation of selenous acid (H
2SeO
3) with halogens, such as chlorine or bromine, or with potassium permanganate. However, using chlorine or bromine as the oxidising agent also produces hydrochloric or hydrobromic acid as a side-product, which needs to be removed from the solution since they can reduce the selenic acid to selenous acid.
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Wikipedia