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Monocalcium aluminate

Monocalcium aluminate
Names
IUPAC name
Monocalcium aluminate
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • 234-931-0
  • InChI=1S/2Al.Ca.4O/q;;+2;;;2*-1
    Key: XFWJKVMFIVXPKK-UHFFFAOYSA-N
  • [O-][Al]=O.[O-][Al]=O.[Ca+2]
Properties
CaAl2O4
Molar mass 158.038676 g/mol
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H315, H318, H319, H332
P261, P264, P271, P280, P302+P352, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P332+P313, P337+P313, P362
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Monocalcium aluminate (CaAl2O4) is one of the series of calcium aluminates.[1] It does occur in nature, although only very rarely, as two polymorphs known as krotite and dmitryivanovite, both from meteorites.[2][3] It is important in the composition of calcium aluminate cements.

Properties

Monocalcium aluminate is formed when the appropriate proportions of calcium carbonate and aluminium oxide are heated together until the mixture melts. It melts incongruently at 1390 °C. The crystal is monoclinic and pseudohexagonal, and has density 2945 kg·m−3. In calcium aluminate cements, it exists as a solid solution in which the amount of minor elements depends upon the bulk composition of the cement. A typical composition[4] is Ca0.93Al1.94Fe0.11Si0.02O4. It reacts rapidly with water, forming the metastable hydrate CaO·Al2O3·10H2O, or a mixture of 2CaO·Al2O3·8H2O, 3CaO·Al2O3·6H2O and Al(OH)3 gel. These reactions form the first stage of strength development in calcium aluminate cements.

References

  1. ^ H F W Taylor, Cement Chemistry, Academic Press, 1990, ISBN 0-12-683900-X, p 35
  2. ^ "Dmitryivanovite".
  3. ^ "Krotite".
  4. ^ P. C. Hewlett (Ed)Lea's Chemistry of Cement and Concrete: 4th Ed, Arnold, 1998, ISBN 0-340-56589-6, p715
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