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A New Calcium Oxalate Monohydrate Produced by Thermal Dehydration of Weddellite
Author(s) -
Schubert G.,
Ziemer B.
Publication year - 1981
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19810160913
Subject(s) - orthorhombic crystal system , crystallography , chemistry , phase (matter) , materials science , crystal structure , organic chemistry
A high temperature‐Guinier photograph of weddellite power showed at 118 °C a transition to a so far unknown phase which transformed to β‐Ca(COO) 2 at 135 °C and during cooling down to whewellite at 103 °C. X‐ray diffraction studies on single crystals revealed the new phase to have an orthorhombic symmetry with the lattice constant a = 12.088 Å, b = 10.112 Å, c = 14.634 Å, α = β = γ = 90°. There are very simple orientation relations to weddellite: a 1 (wed) ∥ a (new phase), a 2 (wed) ∥ b (new phase), c (wed) ∥ c (new phase). DTA/TG studies showed that the new phase is a calcium oxalate monohydrate.