Abstract. Mr= 665-74, triclinic, P], a = 16.428 (5), b=12.122(4), c=6.954(1)A, ct=97.61(2), fl= 77-36 (2), y=110.09(2) ° , V=1266.52A 3, Z=2, Dm(flotation ) = 1.72, D~= 1.74 g cm -3, /~(Mo Ka) = 6.3cm -1, 2=0.71069A, F(000)=676, T=294K, final R = 0.054 for 4724 reflections with F o > 3a(Fo).The structure consists of one Na ÷ and two independent K + cations, three independent C7HaNO3S -anions and one H20 molecule, in a polymeric framework. The anions are bonded to the cations through the N as well as the carbonyl and sulphonyl O atoms. The H20 molecule forms bridges between two Na + and between one Na ÷ and one K ÷ ion, and is also involved in H bonds with the carbonyl groups of two CvH4NO3S-anions.
Introduction.Previous work has shown that octaphenylcyclotetrasiloxane is polymorphic, occurring in monoclinic and triclinic forms and also as a benzene solvate (Hyde, Frevel, Nutting, Petrie & Purcell, 1947). As part of an investigation of the structure and conformation of cyclosiloxanes and related species, we have begun a crystallographic study of this system. Here we report the analysis of the monoclinic form.The compound was prepared by the condensation of phenylsilanediol in alkaline medium and recrystallized from benzene-95% ethanol to obtain colourless needles. The cell parameters were initially determined from photographs and subsequently refined on a Nonius CAD-4 diffractometer from the setting angles for 25 reflections. The intensities of 7191 reflections (3 < 0 < 60 °) were recorded on the diffractometer with Ni-filtered Cu K~ radiation, an 09--20 scan technique and a crystal 0.40 x 0.15 x 0.12 mm. Two reference reflections, measured periodically, showed only minor fluctuations. The intensities were corrected for Lp factors but not for absorption. 4009 unique reflections with F o > 3a(Fo) were considered observed and used in the analysis.The structure was determined by direct methods and refined by a full-matrix least-squares procedure to a
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.