حمض اليوديك

حمض اليوديك
الأسماء
	أسماء أخرى Iodic(V) acid
Identifiers
رقم CAS
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:24857 ;
ChEMBL	ChEMBL1161636 ;
ChemSpider	22761 ;
ECHA InfoCard	100.029.056
PubChem CID	24345;
CompTox Dashboard (EPA)	DTXSID2064812 ;
InChI	InChI={{{value}}}
SMILES
الخصائص
الصيغة الجزيئية	HIO3
كتلة مولية	175.91 g/mol
المظهر	White solid
الكثافة	4.62 g/cm3, solid
نقطة الانصهار
قابلية الذوبان في الماء	269 g/100 mL (20 °C)
الحموضة (pKa)	0.75
القابلية المغناطيسية	−48.0·10−6 cm3/mol
المخاطر
خطر رئيسي	acid, corrosive, oxidant
ن.م.ع. مخطط تصويري
ن.م.ع. كلمة الاشارة	Danger
NFPA 704 (معيـَّن النار)	0 3 1 OX
نقطة الوميض	Non-flammable
مركبات ذا علاقة
كاتيونات أخرى	Lithium iodate; Potassium iodate
هالوجين oxoacids ذات العلاقة	حمض الكلوريك; حمض البروميك
مركـّبات ذات علاقة	حمض اليوديك المائي; Iodine pentoxide; Periodic acid
	ما لم يُذكر غير ذلك، البيانات المعطاة للمواد في حالاتهم العيارية (عند 25 °س [77 °ف]، 100 kPa).
	verify (what is ?)
	مراجع الجدول

حمض اليوديك Iodic acid، HIO₃، يمكن الحصول عليه كمادة صلبة بيضاء أو شبه بيضاء. It dissolves in water very well, but it also exists in the pure state, as opposed to chloric acid or bromic acid. Iodic acid contains iodine in the oxidation state +5 and it is one of the most stable oxo-acids of the halogens in its pure state. When iodic acid is carefully heated, it dehydrates to iodine pentoxide. On subsequent heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.

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التحضير

Iodic acid can be produced by oxidizing $I 2$ with strong oxidizers such as Nitric acid $HNO 3$ , Chlorine $Cl 2$ , حمض الكلوريك $HClO 3$ or Hydrogen peroxide $H 2 O 2$ ,^[2] for example :

{\ce {I2 + 6 H2O + 5Cl2 <=> 2 HIO3 + 10 HCl}}

البنية

Iodic acid crystallises from acidic solution as orthorhombic α-HIO 3 in space group P2₁2₁2₁. The structure consists of pyramidal molecules linked by hydrogen bonding and intermolecular iodine-oxygen interactions. The I=O bond lengths are 1.81 Å while the I–OH distance is 1.89 Å.^[3]^[4]^[5] Several other polymorphs have been reported, including an orthorhombic γ form in space group Pbca^[6] and an orthorhombic δ form in space group P2₁2₁2₁.^[7] All of the polymorphs contain pyramidal molecules, hydrogen bonding and I···O interactions, but differ in packing arrangement.

الخصائص

Iodic acid is a relatively strong acid with a pK_a of 0.75. It is strongly oxidizing in acidic solution, less so in basic solution. When iodic acid acts as oxidizer, then the product of the reaction is either iodine, or iodide ion. Under some special conditions (very low pH and high concentration of chloride ion, e.g. in concentrated hydrochloric acid), iodic acid is reduced to iodine trichloride, a golden yellow compound in solution and no further reduction occurs. In the absence of chloride ions, when there is an excess amount of reductant, then all iodate is converted to iodide ion. When there is an excess amount of iodate, then part of the iodate is converted to iodine.It may be used in preparation of ionization to form alkyl halide

الاستخدامات

Iodic acid is used as a strong acid in analytical chemistry. It may be used to standardize solutions of both weak and strong bases, with methyl red or methyl orange as the indicator.

الاستخدام في صناعة الملح

Iodic acid can be used to synthesize sodium or potassium iodate for increasing iodine content of salt.^{[بحاجة لمصدر]}

الأحماض الأكسجينية الأخرى

Iodate is part of a series of oxyacids in which iodine can assume oxidation states of −1, +1, +3, +5, or +7. A number of neutral iodine oxides are also known.

Iodine oxidation state	−1	+1	+3	+5	+7
Name	Hydrogen iodide	Hypoiodous acid	Iodous acid	Iodic acid	Periodic acid
Formula	HI	HIO	HIO₂	HIO₃	HIO₄ or H₅IO₆

الهامش

^ "Iodic acid" (PDF) (in الإنجليزية).
^ (بالألمانية) Arnold F. Holleman, Nils Wiberg, « Lehrbuch der Anorganischen Chemie », 102. Auflage, Berlin, 2007. ISBN 978-3-11-017770-1
^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 863. ISBN 978-0-08-037941-8.
^ Rogers, Max T.; Helmholz, Lindsay (1941). "The Crystal Structure of Iodic Acid". J. Am. Chem. Soc. 63 (1): 278–284. doi:10.1021/ja01846a068.
^ Ståhl, Kenny; Szafranski, Marek (1992). "A Single-Crystal Neutron Diffraction Study of HIO₃ at 295 and 30 K and of DIO₃ at 295 K". Acta Chem. Scand. 46: 1146–1148. doi:10.3891/acta.chem.scand.46-1146.
^ Fischer, Andreas; Lindsjö, Martin (2005). "γ-HIO₃ – a Metastable, Centrosymmetric Polymorph of Iodic Acid". Z. Anorg. Allg. Chem. 631 (9): 1574–1576. doi:10.1002/zaac.200500099.
^ Wu, Tao; Zavalij, Peter Y.; Zachariah, Michael R. (2017). "Crystal structure of a new polymorph of iodic acid, δ-HIO₃, from powder diffraction". Powder Diffraction. 32 (4): 261–264. Bibcode:2017PDiff..32..261W. doi:10.1017/S0885715617000859. S2CID 104100313.

[1] "Iodic acid" (PDF) (in الإنجليزية).

[2] (بالألمانية) Arnold F. Holleman, Nils Wiberg, « Lehrbuch der Anorganischen Chemie », 102. Auflage, Berlin, 2007. ISBN 978-3-11-017770-1

[3] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 863. ISBN 978-0-08-037941-8.

[4] Rogers, Max T.; Helmholz, Lindsay (1941). "The Crystal Structure of Iodic Acid". J. Am. Chem. Soc. 63 (1): 278–284. doi:10.1021/ja01846a068.

[5] Ståhl, Kenny; Szafranski, Marek (1992). "A Single-Crystal Neutron Diffraction Study of HIO₃ at 295 and 30 K and of DIO₃ at 295 K". Acta Chem. Scand. 46: 1146–1148. doi:10.3891/acta.chem.scand.46-1146.

[6] Fischer, Andreas; Lindsjö, Martin (2005). "γ-HIO₃ – a Metastable, Centrosymmetric Polymorph of Iodic Acid". Z. Anorg. Allg. Chem. 631 (9): 1574–1576. doi:10.1002/zaac.200500099.

[7] Wu, Tao; Zavalij, Peter Y.; Zachariah, Michael R. (2017). "Crystal structure of a new polymorph of iodic acid, δ-HIO₃, from powder diffraction". Powder Diffraction. 32 (4): 261–264. Bibcode:2017PDiff..32..261W. doi:10.1017/S0885715617000859. S2CID 104100313.

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