ChemInform Abstract: Low‐ and High‐Temperature Crystal Structures of TiI₃.

Abstract

Structure D 2000Low-and High-Temperature Crystal Structures of TiI3. -The title compound is characterized by single crystal XRD at different temperatures. At 326 K TiI 3 crystallizes in the hexagonal space group P63/mcm with Z = 2 (TiI3-type structure). At 100 and 273 K it crystallizes in the orthorhombic space group Pmnm with Z = 4 (RuBr3-type structure). The high-temperature structure contains chains of equidistant Ti atoms. A twofold superstructure develops below 323 K, resulting in the low-temperature structure that is characterized by a dimerization of the metal chains. -(ANGELKORT, J.; SCHOENLEBER, A.; VAN SMAALEN*, S.; J. Solid State Chem. 182 (2009) 3, 525-531; Lab. Crystallogr., Univ. Bayreuth, D-95440 Bayreuth, Germany; Eng.) -W. Pewestorf 25-002

Layered α-TiCl3: Microsheets on YSZ Substrates for Ethylene Polymerization with Enhanced Activity

“…According to the ionic nature of TiCl 3 , the d 1 configuration of the Ti 3+ ions tends to establish magnetic spin interactions between the neighboring metal atoms at low temperatures. Thus, a low-temperature phase at 217 K (β-TiCl 3 ) occurs with the antiferromagnetic spin coupling of the d 1 valence electrons and dimerization of Ti atoms. − In fact, TiCl 3 is polymorphic, first described by Klemm, and can appear as one-dimensional chains (β-TiCl 3 ) with face-sharing TiCl 6 octahedra, as two-dimensional layers consisting of edge-sharing TiCl 6 octahedra with hexagonal close packing (α-TiCl 3 ) or cubic close packing of chlorine atoms (γ-TiCl 3 ) with partially filled d shells. ,, Within the close-packed structures (both hexagonal and cubic) two-thirds of the octahedral positions in one layer are occupied by titanium, while one chlorine–chlorine layer remains empty, thus forming the honeycomb-like 2D-structures. That is, the crystallographic α and γ forms only differ in the stacking order of chlorine atom planes and thus are polytypes.…”

Thermal Properties and Phase Transition of 2ZrO2●P2O5 Studied by In Situ Synchrotron X‐ray Diffraction

“…In the low‐temperature phase of TiI 3 , the neighboring metal atoms contribute with ∼0.36 to the valence of the metal atoms. With the transition into the high‐temperature phase of TiI 3 , the metal–metal contribution to the valence of Ti decreases by about ∼0.1 . As the average metal–metal contributions and the values of their changes at the transition are of the same magnitude for the metal atoms in Z 2 P and TiI 3 , the metal–metal interactions seem to possess a similar importance for the formation of the low‐temperature phases for both compounds.…”

“…By cooling of d 1 transition‐metal compounds like TiI 3 and NbO 2 , metal–metal interactions cause phase transitions into low‐temperature phases, in which the metal atoms are grouped into dimers . In the low‐temperature phase of TiI 3 , the neighboring metal atoms contribute with ∼0.36 to the valence of the metal atoms.…”

Exploring the electronic and magnetic properties of new metal halides from bulk to two-dimensional monolayer: RuX3 (X = Br, I)

“…Experimentally RuBr 3 can have Pmnm space group at low temperature while it has P6 3 /mcm space group at high temperatures, and RuI 3 has P6 3 /mcm space group at room temperature. 38 In this paper we study only bulk RuBr 3 and RuI 3 structure in P3 1 12 space group which is valid for RuCl 3 (see Fig. 1).…”