 The iodate anion, IO−3
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 Space-filling model of the iodate anion
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| Identifiers | |
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3D model (JSmol)
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| ChEBI |
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| ChemSpider | |
| 1676 | |
PubChem CID
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| UNII | |
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| Properties | |
| IO3− | |
| Molar mass | 174.902 g·mol−1 |
| Related compounds | |
Related compounds
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Periodate, Fluoroiodate, Bromate, Chlorate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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An iodate is the polyatomic anion with the formula IO−3. It is the most common form of iodine in nature, as it comprises the major iodine-containing ores.[1] Iodate salts are often colorless. They are the salts of iodic acid.
YouTube Encyclopedic
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IO3- Lewis Structure: How to Draw the Lewis Structure for the Iodate Ion
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Vitamin C - Iodide/iodate titration
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Which is better : Potassium Iodate or Potassium Iodide?
Transcription
This is the IO3- Lewis structure: the Iodate ion. For IO3- we have a total of 26 valence electrons. Iodine is the least electronegative. We'll put that at the center, and then we'll put the Oxygens around the outside. We have 26 valence electrons for IO3-. We'll put 2 between atoms to form chemical bonds. We've used 6. Then we'll go around and fill the octets for the Oxygens. We have 6, 8, 10, 24; and then back to the central Iodine, 26. So it looks like we're done: each of the atoms has 8 valence electrons, so the octets are satisfied, and we've used 26 valence electrons. However, when we look at the structure, Iodine is below period 2, row 2 on the periodic table. That means Iodine can have an expanded octet--can have more than 8 valence electrons--so we really need to look at the formal charges here to see if this is the most likely structure for IO3-. For the Iodine--Iodine has 7 valence electrons on the periodic table. Nonbonding, we have 2 right here that are not involved in a chemical bond. Minus bonding, we have 2, 4, 6, which we'll divide by 2. That gives us a +2 formal charge for the Iodine. For the Oxygens, they're all the same so we'll just do one. Oxygen has 6 valence electrons from the periodic table, minus nonbonding; we have 6 nonbonding, minus bonding--2 divided by 2. That gives us a -1 formal charge for each of the Oxygens. We really want our formal charges to be as close to zero as possible. We'll still need to retain the -1, of course. To do that, we can form a double bond with the Oxygen by moving these valence electrons and share them with the Iodine. That'll result in a formal charge of 0 on this Oxygen and a +1 on the Iodine. So we're getting close. Let's form another double bond between this Oxygen and the Iodine. When we do that, this Oxygen has a formal charge of 0, and now the Iodine has a formal charge of 0. We're still using 26 valence electrons, and each of the Oxygen atoms have octets. The Iodine has more than 8, but that's OK because it can have an expanded octet. Our formal charge for this entire structure here shows up to be -1, which makes sense. This is a negative ion. Because the formal charges are close to zero with this structure, that makes this the more likely Lewis structure for IO3-. One last thing: we do need to put brackets and a negative sign around the Lewis structure to show that it's a negative ion. And that's the Lewis structure for IO3-. This is Dr. B., and thanks for watching.
Structure
Iodate is pyramidal in structure. The O–I–O angles range from 97° to 105°, somewhat smaller than the O–Cl–O angles in chlorate.[2]
Reactions
Redox
Iodate is one of several oxyanions of iodine, and has an oxidation number of +5. It participates in several redox reactions, such as the iodine clock reaction. Iodate shows no tendency to disproportionate to periodate and iodide, in contrast to the situation for chlorate.
Iodate is reduced by sulfite:[1]
- 6HSO−3 + 2IO−3 → 2I− + 6HSO−4
Iodate oxidizes iodide:
- 5I− + IO−3 + 3H2SO4 → 3I2 + 3H2O + 3SO2−4
Similarly, chlorate oxidizes iodide to iodate:
- I− + ClO−3 → Cl− + IO−3
Iodate is also obtained by reducing a periodate with a sulfide. The byproduct of the reaction is a sulfoxide.[3]
Acid-base
Iodate is unusual in that it forms a strong hydrogen bond with its parent acid:[2]
- IO−3 + HIO3 → H(IO3)−2
The anion H(IO3)−2 is referred to as biiodate.
Principal compounds
- Calcium iodate, Ca(IO3)2, is the principal ore of iodine. It is also used as a nutritional supplement for cattle.
- Potassium iodate, KIO3, like potassium iodide, has been issued as a prophylaxis against radioiodine absorption in some countries.[4][5] It is also one of the iodine compounds used to make iodized salt.[6]
- Potassium hydrogen iodate (or potassium biiodate), KH(IO3)2, is a double salt of potassium iodate and iodic acid, as well as an acid itself.
- When some oxygen is replaced by fluorine, fluoroiodates are produced.
Natural occurrence
Minerals containing iodate are found in the caliche deposits of Chile. The most important iodate minerals are lautarite and brüggenite, but also copper-bearing iodates such as salesite are known.[7]
Natural waters contain iodine in the form of iodide and iodate, their ratio being dependent on redox conditions and pH. Iodate is the second most abundant form in water. It is mostly associated with alkaline waters and oxidizing conditions.[8]
References
- ^ a b Lyday, Phyllis A. (2005). "Iodine and Iodine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 382–390. doi:10.1002/14356007.a14_381. ISBN 978-3527306732.
- ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Qiu, Chao; Sheng Han; Xingguo Cheng; Tianhui Ren (2005). "Distribution of Thioethers in Hydrotreated Transformer Base Oil by Oxidation and ICP-AES Analysis" (abstract). Industrial & Engineering Chemistry Research. 44 (11): 4151–4155. doi:10.1021/ie048833b. Retrieved 2007-05-03.
Thioethers can be oxidized to sulfoxides by periodate, and periodate is reduced to iodate
- ^ "Radiological Protection Institute of Ireland | | Media | Press releases | Radioactivity released from Wylfa nuclear power plant is extremely low and of no health significance". Archived from the original on 2013-10-17. Retrieved 2013-04-08.
- ^ "Decision to Discontinue the Future Distribution of Iodine Tablets". Archived from the original on 2013-10-18. Retrieved 2013-05-22.
- ^ Arroyave, Guillermo; Pineda, Oscar; Scrimshaw, Nevin S. (1956) [May 1955]. "The stability of potassium iodate in crude table salt". Bulletin of the World Health Organization. 14 (1): 183–185. PMC 2538103. PMID 13329845.
- ^ "Home". mindat.org.
- ^ Sweden (13 December 2013). "Iodine (including PVP-iodine) Product types 1, 3, 4, 22 (EU 528/2012 assessment)". pp. 29–30.
This page was last edited on 15 March 2024, at 07:58