Liquids, quasi-crystalline structure

Andrade,5 on the basis of the quasi-crystalline structure of liquids, deduced ... 

Another characteristic point is the special attention that in intermetallic science, as in several fields of chemistry, needs to be dedicated to the structural aspects and to the description of the phases. The structure of intermetallic alloys in their different states, liquid, amorphous (glassy), quasi-crystalline and fully, three-dimensionally (3D) periodic crystalline are closely related to the different properties shown by these substances. Two chapters are therefore dedicated to selected aspects of intermetallic structural chemistry. Particular attention is dedicated to the solid state, in which a very large variety of properties and structures can be found. Solid intermetallic phases, generally non-molecular by nature, are characterized by their 3D crystal (or quasicrystal) structure. A great many crystal structures (often complex or very complex) have been elucidated, and intermetallic crystallochemistry is a fundamental topic of reference. A great number of papers have been published containing results obtained by powder and single crystal X-ray diffractometry and by neutron and electron diffraction methods. A characteristic nomenclature and several symbols and representations have been developed for the description, classification and identification of these phases. 

Free suspended films of smectic liquid crystals can show a change in the crystalline order from the quasi-two-dimensional to the three-dimensional one [11]. Very thin smectic B films (number of monolayers n < 10) are two dimensional with the hexatic in-plane order, and with (low temperatures) or without (higher temperatures) a tilt of molecules. With increasing n (n > 20) the transition to various three-dimensional crystalline structures is observed. 

In 8 1 it was shown that equations (14 4)-(14 6) lead to a statistical deduction of the laws of ideal solutions. For this purpose it was supposed that a solid or liquid solution can be approximated by a quasi-crystalline lattice, and also that the A and B molecules are of a sufficiently equal shape and size for them to be interchangeable between the lattice sit without change of lattice structure and without change in the lattice vibrations or the internal states of the molecules. Before mixing there is only one geometrical arrangement and after mixing there are... 

Monomer B5A can be photopolymerized at room temperature in its Sg phase to near completion with little volume change. The smectic liquid crystalline structure is retained and locked into the resulting polymeric network upon polymerization. This can be attributed to the topochemical control exerted by the LC monomer matrix on the as-formed polymer a quasi-topochemical polymerization reaction is involved (B5A-RT and PB5A-RT has almost the same unit cell parameters). Fixation of the LC structure is realized through cross-linking, which severely restricts molecular motion and relaxation. The LC structure is maintained up to very high temperatures. This could extend the application temperature of... 

A review entitled New phosphorus-tellurium heterocycles in the quasi-binary system RP/Te , which contains and Te NMR data, has appeared. H/ H isotope effect on the translational and rotational motion of liquid water and ammonia has been assessed by NMR measurements.The diffusion of ammonia in binary mixtures has been investigated using the pulsed-field gradient technique. A quantitative structure-property relationship of the P NMR chemical shifts has been developed for a large set of phosphines.The NMR spectrum of [P(CF3)2] has been analysed as X3MAY3 and determined.An iterative lineshape analysis of N NMR spectra of [N3] has been described. and P NMR studies of a liquid-crystalline cyclotriphos-... 

---