A Reexamination of the Polymorphism of Ca ₃ SiO ₅

Abstract

Polymorphic transitions in CasSiO 6 have been investigated by precise high‐temperature X‐ray diffractometer measurements and by differential thermal analyses. In addition to change caused by normal thermal expansion, three principal crystallographic transformations take place: α‐triclinic–β–triclinic (sluggish) in the range 550° to 700°C; 8‐triclinic‐monoclinic at 910°± 10°C; and monoclinic‐trigonal at 970°± 10°C. The sluggish 550° to 700° C reaction alternatively may be interpreted as two separate triclinic‐triclinic transitions, accompanied by broad endothermic heat effects at 575° and 675°C.