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An X-ray examination of calcium formate

Published online by Cambridge University Press:  14 March 2018

Kathleen Yardley
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Extract

Calcium formate, (HCOO)2Ca, is soluble in cold water, from which it crystallizes by slow evaporation. Groth gives the following data concerning the crystals of this substance :

Specific gravity (mean value) 2.019.

Orthorhombic bipyramidal ; a : b : c = 0.7599 : 1 : 0.4681.

The molecular weight is 130.1. No definite cleavage has been observed, nor does twinning occur. There seems to have been some difference of opinion regarding the degree of symmetry. Originally the crystals were described as orthorhombic (holohedral) by J. C. Heusser in 1851, and this was followed by V. von Lung (1858) and A. Schrauf (1861). Later, however, Plathan claimed to have observed unsymmetrical etch-figures which would prove the crystal to be bisphenoidal (like the strontium, barium, and lead formates), but Wagner found only etch-figures in accordance with what would be expected from bipyramidal symmetry.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 20 , Issue 108 , March 1925 , pp. 296 - 298
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1925

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References

Page 296 note 1 Groth, P., Chem. Kryst., 1910, vol. 8, p. 12 Google Scholar.

Page 296 note 2 Plathan, A., [Diss., Helsingfors, 1897], abstract in Zeits. Anorg. Chem., 1898, vol. 18, p. 86 Google Scholar.

Page 296 note 3 Wagner, L., Zeits. Kryst. Min., 1911, vol. 50, p. 49 Google Scholar.

Page 298 note 1 Astbury, W. T. and Yardley, K., Phil. Trans. Roy. Soc. London, 1924, ser. A, vol. 224, p. 221 CrossRefGoogle Scholar. [Min. Abstr., vol. 2, p. 866.]