オルト過ヨウ素酸

外観

無色〜ごくうすい褐色, 澄明の液体

溶解性

水に易溶 (112g/100ml, 25℃), エタノールに可溶, エーテルに微溶。水に極めて溶けやすく、エタノールにやや溶けやすい。

解説

オルト過ヨウ素酸，市販品では，この物質を過ヨウ素酸とよぶが，IUPACでは両者を区別している．融点約130 ℃．過ヨウ素酸水溶液中では，次の平衡が成立している．　　H5IO6⇄ H＋ ＋ H4IO6－(K 1×10－3)　　H4IO6－⇄ IO4－ ＋ 2H2O(K 29)　　H4IO6－⇄ H＋ ＋ H3IO62－(K 2×10－7)25 ℃ の水溶液ではIO4－がおもなイオンである．

森北出版「化学辞典（第2版）

用途

PAS反応の酸化剤。

用途

分析用試薬、酸化滴定用、有機化合成用(酸化剤)。

性質

オルト過ヨウ素酸，IⅦのオキソ酸としては，過ヨウ素酸HIO4より安定である．

使用上の注意

潮解性あり

化学的特性

PERIODIC ACID is colourless crystals

物理的性質

In dilute solution, periodic acid exists as H⁺ and IO4^-. When more concentrated, orthoperiodic acid, H5IO6, is formed. Note that this compound is essentially a dihydrate, HIO4·2H2O. This can be obtained as a crystalline solid. O-periodic acid can be dehydrated to metaperiodic acid, m-HIO4. Further heating gives di-iodine pentoxide (I2O5) and O2. The anhydride di-iodine heptoxide, i.e. I2O7, does not exist in nature but can be formed synthetically.

使用

PERIODIC ACID is used as an oxidiser and in the determination of manganese.

反応性

Paraperiodic acid H5IO6, is obtained from sodium paraperiodate, formed by action of chlorine upon a NaOH solution containing I2. On vacuum drying, paraperiodic acid yields metaperiodic acid, HIO4, and dimesoperiodic acid, H4I2O9; which form heteropoly acids with a number of oxides and acids. The periodic acids and their salts are strong oxidizing agents both with inorganic and organic compounds.

一般的な説明

Periodic acid (H₅IO₆) is an oxoacid of iodine. It is commonly used as an oxidizing agent in organic synthesis for the preparation of useful chemical intermediates. Periodic acid is also used in oxidative cleavage reactions.