Structural chemistry of bimetallic hydride complexes of titanium and aluminium: I. Crystal and molecular structure of [(η5-C5H5)2,Ti(μ-H)2AlH2]2(CH3)2NCH2CH2N(CH3)2C6H6

The structure of a titanium aluminium hydride complex of composition [(C₅H₅)₂TiAlH₄]₂(CH₃)₂NC₂H₄N(CH₃)₂C₆H₆ has been determined by X-ray diffraction. The complex forms triclinic crystals with unit cell dimensions a = 8.406(2), b = 10.117(2), c = 11.269(3) Å; α = 112.01(2)°, β = 109.25(2)°, γ = 87.04(2)°, space group P$\text{1}$, Z = 2 and density d = 1.21 g/cm³. The structure was refined to give a discrepancy index R = 0.056. The crystals are composed of centrosymmetric molecules of (Cp₂TiAlH₄)₂TMEDA (Cp = η⁵-cyclopentadienyl) and molecules of crystal benzene. Two moieties of Cp₂TiH₂AlH₂ are linked by a tetramethylethylenediamine molecule (r_AlN 2.11 Å). The aluminium atom is bonded to a titanium atom by a double hydride bridge (r_AlH b = 1.8, 1.6 Å, r_TiH b = 1.6 Å), and has trigonal bipyramidal stereochemistry, [H₄N] (r_AlH t = 1.6 Å).     

The abrupt changes in the yellowed fibril density in the Linen of Turin

The present investigation is an attempt to explain the abrupt changes in the yellowed fibril density (or image intensity) values in the dorsal part of the Shroud of Turin body image. The interested areas are the ones at the base of the shoulders and the buttocks. These rapid changes in the body image intensity are not anomalies of the linen manufacture. They can be explained with the original presence of aromas and/or burial ointments.     

Stochastic distribution of the fibrils that yielded the Shroud of Turin body image

The fibrils that yielded the Shroud body image show a stochastic distribution on the Linen of Turin. In fact, the probability of a fibril yellowing is a function of the energy, while this is not the case for the optical density value. This means that the above image is a latent image. We suggest thermal radiation or low-temperature chemical processes as possible natural energy sources to explain, by stochastic effects, the Shroud body image formation. Unfortunately, due to the nature of the phenomenon, we are not able to extract the energy source.     

Constructing an international library: The collections of journals in Turin's Special Mathematics Library

The Special Mathematics Library of Turin University, founded in 1883, was fundamental in the development of two research schools under the leadership of C. Segre and G. Peano. First founded to house a growing collection of international journals acquired through both purchase and exchange from publishing centres worldwide, it later evolved into a ‘presence library’ modelled on the legendary Lesezimmer in Göttingen. A systematic study of the library's history and its directors' policies provides interesting insights into the various aspects of the international circulation of journals and their use at different times and in various contexts in Turin (Turin Academy of Sciences, Società di cultura, national university library, etc.).     

Can a latent image explain the characteristics of the Shroud body image?

The distribution of the fibrils that have yielded the body image on the Shroud is stochastic. In this paper, we show that the hypothesis of latent image can explain the chemical and physical characteristics of the above body image. It is also concluded that the “Shroud question” requires new radiocarbon dating done on a sample selected after careful chemical analysis.