A Reexamination of the Polymorphism of Ca₃SiO₅

Abstract

Polymorphic transitions in CasSi06 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 : atriclinic-@-triclinic (sluggish) in the range 550" to 700°C ; 8-triclinic-monoclinic at 910" f 10°C ; and monoclinic-trigonal at 970" =t 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.