XEF2-CENTER-DOT-2CRF(4) AND XEF5- - SYNTHESES, CRYSTAL-STRUCTURES, AND SOME PROPERTIES(CRF5)

XeF2. 2CrF(4) was prepared by solvolysis of XeF2. CrF4 in anhydrous hy drogen fluoride (aHF) and subsequent decantation of the majority of di ssolved XeF2 in aHF. Remaining XeF2 and a large excess of CrF4 form Xe F2. 2CrF(4) after aHF is removed. Ruby-red single crystals were obtain ed either by healing the sample in a thermal gradient or by recrystall ization in supercritical SF6. The compound crystallizes in the triclin ic space group P (1) over bar with a = 855.1(3) pm, b = 922.1(3) pm, c = 1043.8(3) pm, alpha = 76.02(2)degrees, beta = 81.36(2)degrees, gamm a 88.08(3)degrees, and Z = 4 at 293 K. The basic structural unit is fo rmed by four independent Cr atoms, each octahedrally coordinated by si x F atoms. Two fluorine ligands are provided by two different XeF2 mol ecules. The distorted octahedra are connected via common F atoms to fo rm a three-dimensional network. XeF5+CrF5- was prepared from XeF6 and CrF4 at room temperature or by the reaction of XeF6 and CrF5 at 333 K. Red single crystals were grown from the solution of XeF5+CrF5- in aHF . The compound crystallizes in the orthorhombic space group Pbca with a = 1828.1(13) pm, b = 842.9(7) pm, c 1852.1(12) pm, and Z = 16 at 268 K. The main structural feature is formed by an infinite chain of dist orted CrF6 octahedra joined via cis vertexes, while XeF5+ cations comp ensate the negative charge of each octahedron.