Redetermination of the crystal structure of ThI₄

Abstract

Single crystals of ThI4, thorium(IV) tetraiodide, were grown from thorium dioxide and aluminium triiodide. In comparison with the structure model reported previously for this compound [Zalkinet al.(1964).Inorg. Chem.3, 639–644], we have determined the lattice parameters and fractional coordinates to a much higher precision, also leading to a better reliability factor (R= 0.029versus0.09). The coordination number of the ThIVatom is eight. Its coordination polyhedron has the shape of an irregular square antiprism. The I atoms each bridge two ThIVatoms, resulting in the formation of infinite layers parallel to (-101) that can be described with the Niggli formula2∞[ThI6/2I2/2].

Stabilization of Pu(IV) in PuBr4(OPCy3)2 and Comparisons with Structurally Similar ThX4(OPR3)2 (R = Cy, Ph) Molecules

“…Binary ThI 4 has been characterized as an eight-coordinate metal center with four μ–iodide anions and can be viewed as [Th IV (μ–I) 4 ] ∞ . The Th–I bond lengths of ThI 4 range from 3.1324(7)–3.2896(7) Å, similar to the 3.148(7)–3.2739(5) Å Th–I bond lengths of [Th­(μ–I)­I 3.22 (OEt) 0.78 (Et 2 O) 2 ] 2 ; both are significantly longer than the 3.0218(5) Å bond length in Th IV I 4 (Et 2 O) 2 , likely due to the weak donating ability of diethyl ether, Table . The 0.060 Å difference in An–I bond lengths for Th IV I 4 (Et 2 O) 2 and U IV I 4 (Et 2 O) 2 ,, are greater than the 0.05 Å difference given for the six-coordinate Th IV and U IV ions, while the An–OEt 2 bond lengths only differ by 0.036 Å, Table .…”

“…With the successful synthesis of ThCl/Cy and ThBr/Cy , efforts turned to extend the work to thorium iodide. Thorium tetraiodide has been shown to be difficult to work with, displaying rapid hydrolysis or activating organic solvents such as DME or THF (DME = CH 3 OCH 2 CH 2 OCH 3 , THF = OC 4 H 8 ) upon halide exchange using Me 3 Si–I. , Although binary ThI 4 has been synthesized by high-temperature methods, , we sought an ambient temperature, solution-based method analogous to uranium chemistry. Taking inspiration from the synthesis of U IV I 4 (Et 2 O) 2 from U(0) and I 2 in Et 2 O, Th(0) was combined with two equivalents of I 2 in Et 2 O in dry anaerobic conditions.…”