Crystal Structure of Te2O3F2

Te2O3F2crystallizes with the triclinic symmetry (space groupP-1) and the unit cell parametersa= 515.3(1) pm,b= 625.7(1) pm,c= 688.8(1) pm, α = 98.71(1)°, β = 110.31(1)°, γ = 92.72(1)°,Z= 2. Its structure was solved and refined toRvaluesR1= 0.024 and wR2= 0.059 on the basis of 699 independent reflections recorded on a single crystal with an automatic four-circle diffractometer. The two Te atoms are, respectively, fourfold and fivefold coordinated and their lone pairEis stereochemically active. The bond valence calculation shows a perfect O/F order. The Te(1)O3FEand Te(2)O4FEpolyhedra form, by sharing O–O edges, bipolyhedral units with a very short Te–Te distance (319 pm). These units, by sharing corners, constitute independent sheets parallel tox0y. All the F atoms are nonbridging and orientated, together with the lone pairsE, toward the interlayer space. The structural relationships with the α-TeO2structure have been evidenced and analyzed.