Bis(tetraphenylarsonium) hexafluoridotechnetate(IV) dihydrate: preparation, structure and spectroscopic analysis

Reports of quadrivalent transition‐metal fluoride salts containing bulky organic cations are limited. In this context, we prepared the bis(tetraphenylarsonium) hexafluoridotechnetate(IV) dihydrate salt, (C 24 H 20 As) 2 [TcF 6 ]·2H 2 O, by a cation metathesis reaction of (NH 4 ) 2 [TcF 6 ] in water. This is the first report of an arsonium salt of the hexafluoridotechnetate(IV) dianion. (AsPh 4 ) 2 [TcF 6 ]·2H 2 O crystallizes in the triclinic space group P . The [TcF 6 ] 2− anion adopts a slightly distorted octahedral geometry with an average Tc—F bond length of 1.933 Å. The cyclic voltammogram of (AsPh 4 ) 2 [TcF 6 ]·2H 2 O in CH 3 CN shows a one‐electron reversible oxidation wave at 1.496 V.