Melt crystallization data types

The melting temperatures for the thirty-one elements, whose inelastic neutron scattering data are available, were calculated and compared against the observed melting temperatures as shown in Table 1. In this calculation, the thirty-one elements are sorted into three groups according to their crystal structure type. Different correction factor, A,... 

Several other types of time-resolved PXR experiments are ongoing, including melting, crystallization, and dissociation of simple molecular species that will allow calibration of the PXR system and provide a data base necessary for subsequent large molecule diffraction experiments Other applications including time-resolved molecular holography, plasma diagnostics, and x-ray diffraction of metastable species are also feasible. 

CejRhSij is isostructural with the structure type of ErjRhSij (Chevalier et al., 1984) crystal data as derived from X-ray powder diffraction of arc-melted samples annealed at 800°C, 4 d, were as follows P62c, a = 8.210(5), c = 8.410(5). Cc2RhSi3 is antiferromagnetic below = 6 K paramagnetic susceptibilities (1.5-300 K) correspond to trivalent cerium jaff = 2.40 gg, 6p= — 83 K (Chevalier et al., 1984). 

The existence of a phase PrRu3Si2 with the LaRujSi -type structure was reported by Barz (1980). No crystal data have been presented. For sample preparation and melting behavior (phase equilibria), see also LaRu3Si2-... 

At variance with the crystal data obtained by Rieger and Parthe (1969a) from arc-melted samples, landelli (1983) reported the existence of a compound YCuSi with the ordered Ni2 In-type [superstructure of the AIBj-type P63/mmc, a = 4.147(1), c = 7.448(5)]. The superstructure reflections were said to be faint and were observed from arc-melted samples annealed at 750°C for 8-12 d. The Nijin phase thus was concluded to be a low temperature modification. For detailed sample preparation and purity of starting materials, see LaCuSi. 

ErLiGe (2) was found to crystallize with a ZrNiAJ type with lattice parameters a= 0.7005, c=0.4214 (Pavlyuk 1989 Pavlyuk et al. 1991a) from X-ray powder diffraction of arc melted in a purified Ar atmosphere under a pressure of 1.01 x 10 Pa samples which were annealed in Ta containers at 470 K for 240 h. Purity of the starting components was 99.82 mass% Er, 98.2mass% Li and 99.999 mass% Ge. Czybulka et al. (1990) confirmed the crystal structure for the compound of equiatomic composition, ZrNiAl type, a = 0.6985, c = 0.4219 (X-ray single-crystal data). Chemical analysis gave 33.6 at.% Er, 32.4 at.% Li and 34.0 at.% Ge. For sample preparation, see Ho-Li-Ge. 

According to X-ray single-crystal data, YFe2Ge2 was found to be isostructural with the CeGa2Al2 type, with lattice parameters a = 0.3961, c= 1.0421 (Venturini and Malaman 1996). Samples were prepared from stoichiometric amounts of pure elements. After a first reaction in a silica tube under argon, the mixture was melted in an induction furnace. 

Gladyshevsky et al. (1992) reported on the existence of the CesRuGe2 (7) compound with a S5HfY2-anti-type structure, a = 1.2255,6 = 0.8898, c = 0.8008 (X-ray single-crystal data). The single crystal was obtained from an alloy which was arc melted and annealed at 870 K. 

In order to check the latter point, the powder X-ray diffractogram could be measured for the bulk sample and compared to a calculated spectrum from single crystal data. Visual inspection with a good microscope (with healing to observe different melting points) may also do, often it is quite obvious if all the crystals are of the same type. 

Another recent database, still in evolution, is the Linus Pauling File (covering both metals and other inorganics) and, like the Cambridge Crystallographic Database, it has a "smart software part which allows derivative information, such as the statistical distribution of structures between symmetry types, to be obtained. Such uses are described in an article about the file (Villars et al. 1998). The Linus Pauling File incorporates other data besides crystal structures, such as melting temperature, and this feature allows numerous correlations to be displayed. 

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