Monocalcium aluminate
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| IUPAC name
Monocalcium aluminate
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3D model (JSmol)
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| CaAl2O4 | |
| Molar mass | 158.038676 g/mol |
| Hazards | |
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| 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
[edit]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
[edit]- ^ H F W Taylor, Cement Chemistry, Academic Press, 1990, ISBN 0-12-683900-X, p 35
- ^ "Dmitryivanovite".
- ^ "Krotite".
- ^ P. C. Hewlett (Ed)Lea's Chemistry of Cement and Concrete: 4th Ed, Arnold, 1998, ISBN 0-340-56589-6, p715