Silicate transformations: rhodonite–wollastonite

The effective volumes of waters of crystallization: general organic solids

“…Hofmann (2002) has reported a value of the volumetric coefficient of thermal expansion of 95 Â 10 À6 K À1 for organic materials. Similarly, we have earlier (Glasser, 2019b) found a value of about 100 Â 10 À6 K À1 for paracetamol among the pharmaceutical pairs and, as noted below, now find a mean value of 147 AE 56 Â 10 À6 K À1 among general organic materials (Nyman & Day, 2016) (see Figs. 1 and 2, and Table S1 in the supporting information) with a mode value of 109 Â 10 À6 K À1 .…”

“…We have recently examined effective volumes for both ionic solids (Glasser, 2019a) and non-ionic pharmaceutical systems (Glasser, 2019b). For these systems, we observe that hydrate water effective volumes extend to a seeming upper limit of about 30 Å 3 , which corresponds to the formula volume of liquid water under ambient conditions (but less than the 32 Å 3 observed for the hydrogen-bonded structure of hexagonal ice) and down towards zero as a consequence of the hydration water occupying gaps in the anhydrate, together with the anhydrate's possible structural re-arrangement.…”

The ultrastructure of pyroxenoid chain silicates. III. Intersecting defects in a synthetic iron–manganese pyroxenoid

“…The existence of defects of the types reported confirms the original suggestion (Liebau, 1972) that the pyroxenoids form a continuous structural series, adapting to variations in cation size/ pressure/temperature in a continuous manner. Transformations between different structural types have also been reported (Dent-Glasser & Glasser, 1961;Akimoto & Syono, 1972;Maresch & Mottana, 1976) and it has been assumed that variations in chain repeats within certain samples represent a situation where such transformations are frozen into the structure.…”

The ultrastructure of pyroxenoid chain silicates. I. Variation of the chain configuration in rhodonite

“…Temperature-induced topotactical changes in structure have been observed by single-crystal X-ray methods, for rhodonite/wollastonite (Dent-Glasser & Glasser, 1961) and pyroxmangite/rhodonite (Maresch & Mottana, 1976;Aikawa, 1979) but studies of this type give little indication of the relative sizes and distribution of domains of one structure type within another. These latter factors are important because there should, in principle, be at least one structural configuration, either one of those already known, or one hitherto unreported, for any conditions of formation and composition, in an analogous manner to the behaviour of certain metal oxides (Wadsley, 1964).…”