X-ray powder diffraction data for a new phase of dicalcium silicate, x-Ca2SiO4, are reported. The sample was prepared by the dehydration of hydrothermally synthesized α-type dicalcium silicate hydrate, Ca2(SiO4H)OH, at a temperature of 800 °C. Crystallographic data were Ca2SiO4, monoclinic, P21/c (No. 14), a=8.2127(5), b=9.7930(4), c=9.7954(5) Å, β=94.848(5)°, V=785.00(7) Å3, Z=8, and Dx=2.91 g·cm−3.

The anhydrous acid strontium oxalate Sr(HC2O4)⋅½(C2O4) was obtained by thermal decomposition of the hydrated acid strontium oxalate Sr(HC2O4)⋅½(C2O4)⋅H2O. This non-hygroscopic compound crystallizes in the space group P 21/c (No. 14) with unit cell parameters: a=0.796 61(7) nm, b=0.9205(1) nm, c=0.731 98(8) nm, and β=102.104(8)°. Final refinement of the X-ray powder data yielded RB=3.2% and Rwp=11.1% (background-corrected data). In this structure, Sr is eight-fold coordinated by O. These polyhedra are connected together by edge-sharing to form two-dimensional (2D) layers along the bc-plane, which means that there is an increased dimensionality from 1D to 2D with decreasing water content of the acid oxalates.

X-ray powder diffraction data for synthetic materials MgMnSiO4 and Mg0.6Mn1.4SiO4 are reported. Samples were prepared by firing mixtures of MgO, MnCO3, and SiO2 in prescribed molar ratios at 1523 K. Powder diffraction data were collected with a laboratory X-ray source (CuKα) for refinement of unit-cell parameters and synchrotron radiation (λ=1.1980 Å) for intensity measurement of individual reflections. Crystallographic data were MgMnSiO4, orthorhombic, Pnma (No. 62), a=10.4510(1), b=6.12446(5), c=4.80757(4) Å, V=307.717(4) Å3, Z=4, and Dx=3.697 g·cm−3, and Mg0.6Mn1.4SiO4, orthorhombic, Pnma (No. 62), a=10.5241(1), b=6.17903(6), c=4.83927(5) Å, V=314.692(5) Å3, Z=4, and Dx=3.873 g·cm−3.

A detailed neutron powder diffraction study of the atomic structure of α-Bi2O3 at high temperatures using the Rietveld method was performed to clarify the nature of the unusual magnetic behavior and the origin of the high temperature dielectric anomalies of α-Bi2O3 in the temperature interval 300–700 K. Analysis of obtained experimental data shows that there are no evidence of a structural phase transition in α-Bi2O3 between 295 and 660 K. The observed high temperature dielectric anomalies in α-Bi2O3 are evidently governed by changes in the electron subsystem of the bismuth oxide.

Keeping with tradition, the 2000 MRS annual meeting again took place in Boston Copely Plaza from November 27 to December 1. The 2000 meeting was well organized and well attended, with a total of 4600 attendees representing industrial, academic, and government sectors. The rich technical program was multi-disciplinary (41 symposia) to meet the needs of the attendees. A total of 4000 papers were presented. There were a number of memorable lectures, several special seminars on policy and funding, an award ceremony, a new educational seminar series that focused on the scientific basis and practical application of commercial tools. The meeting also highlighted an elaborate exhibit, poster sessions and other well organized events. This report summarizes various events which took place at the meeting.

X-ray powder diffraction data are reported for a series of multipyrazole compounds in this paper. This work shows that the unit cell dimensions determined by single crystal agree well with those of powder diffraction analysis.