Über Alkali‐ und Erdalkali‐oxorhenate(VII)

Abstract

Darstellung und Eigenschaften von Alkali‐ und Erdalkali‐oxorhenaten(VII) mit den „Sauerstoffzahlen”︁ 5 und 6 werden beschrieben. Die Individualität der einzelnen Verbindungen, die mit den entsprechenden Oxojodaten (VII) und Oxoosmaten (VII)3) isotyp sind, konnte sowohl chemisch wie röntgenographisch sichergestellt werden.

Chemical Trends in Solid Alkali Pertechnetates

“…LiTcO 4 was proposed by Keller and Kanellakopulos to be isostructural to LiReO 4 . The perrhenate compound has reported hydrated and dehydrated forms, with the number of water molecules per formula unit equaling 0 (refs and ; space group P 1̅ per Betz and Hoppe), 1 (refs and ; space group P 2 1 / a per Abakumov et al), 1.5 (refs – ; space group P 2 1 / c per Khrustalev et al), and 2 (refs and ; space group not determined). In the Tc system, crystals with water molecules per formula unit have been reported as 0 (refs , , and ; reportedly isostructural with LiReO 4 ), 2 (ref ; reportedly isostructural with LiReO 4 ·2H 2 O), and 3 (space group P 6 3 / mc according to Maruk et al).…”

Recent advances in the chemistry of rhenium

“…150 The bright yellow mesoperrhenates M^ReOs and Mn3(ReOs)2 are obtained by heating stoichiometric quantities of the metaperrhenates with MI202 (M1 = Na), * ( 1 = K), MnC03 (M11 = Sr), or ( )2 (M11 = Ba) in dry oxygen. 148 Pure M^ReOs ( 1 = K, Rb, and Cs) may be prepared by heating rhenium dioxide and alkali superoxide to 400°for 3 hr, but if peroxide is used in place of superoxide the only product is MIRe04.150•151 These compounds undergo a reversible phase transition at 374°( 1 = K), 320°( M1 = Rb), and 304°( 1 = Cs), but may otherwise be heated to 900°without change .151 On the other hand, the lithium and calcium compounds seem to be so unstable that attempts to prepare them have resulted in mixtures of orthoand metaperrhenates. Strontium mesoperrhenate disproportionates to such a mixture above 750°2…”

Rhenium

“…These are citron yellow oxides or salts isostructural with periodates and osmates(VII) of similar formulae 201 * 206 . The relation between the various barium perrhenates is shown in Table 21.…”

“…Concentrated aqueoUs solutions of perrhenic acid also show a characteristic Raman spectrum which differs from that of perrhenate. In the vapour phase perrhenic acid has been shown to exist as Re03(OH) 206 , but the heating of solid perrhenic acid leads to the volatilization of rhenium heptaoxide. Perrhenic acid is a strong acid; this is shown by the pH of its aqueous solution, its attack upon metals, metal oxides, carbonates, and hydroxides, the behaviour of perrhenates on ion-exchange resins, and the solubility of its salts.…”