Linear Trimeric Hafnium Clusters in Hf 0
The reduction of hafnium tetraiodide, HfI4, with aluminum at 600 °C or 850 °C in the presence of a NaI flux resulted in black single crystals of Hf0.86(1)I3. This composition corresponds well to the upper end of the non-stoichiometry range 0.89 ≤ x ≤ 1.00 previously reported for HfxI3. The crystal structure (a = 1250.3(2), c = 1999.6(3) pm, R-3m, Z = 18) is made up of hexagonal closest packed layers of iodide ions. One third of the octahedral holes would be filled as in TiI3 or ZrI3 if it were Hf1.00I3. In Hf0.86(1)I3, one out of six octahedral holes along [001] are, however, only occupied by 16%. In contrast to TiI3-I and ZrI3, one striking structural feature is in the formation of linear hafnium trimers with identical Hf―Hf distances of 318.3(2) pm rather than the formation of dimers. These may be associated with Hf―Hf bonding although only 2.64 electrons are available for one Hf5.16I18 column.
Yttrium triiodide, YI3
Single crystals of YI3 were obtained by high-vacuum sublimation of the crude product at 1213 K. The crystal structure is that of the BiI3 structure type. Two-thirds of the octa­hedral voids between every second hexa­gonally closest-packed layer of I− ions are occupied by Y3+ ions. Thereby, the YI6 octa­hedra share common edges within Bγ2/3A slabs in the stacking sequence ⋯γ2/3A□Bγ2/3A□Bγ2/3A□Bγ2/3⋯.
Magnetochemische Untersuchungen. XLI. Über das Magnetische Verhalten der Dihalogenide des Titans und Vanadins
Es werden die magnetischen Suszeptibilitaten von TiCl2, TiBr2, TiJ2 und VJ2 bei + 15°, −78° und −183° gemessen. Die Werte zeigen Abweichungen vom reinen Ionenmagnetis-mug, die von den Mangan- zu den Titanverbindungen und von den Jodiden zu den Chloriden zunehmen. Diese Abweichungen werden auf Atombindungen zwischen den Metallionen zuruckgefiihrt.