Dodecacalcium hepta-aluminate

Dodecacalcium hepta-aluminate
	Crystal structure of C12A7
Names
	Other names C12A7; mayenite; Tetradecaaluminum dodecacalcium tritriacontaoxide
Identifiers
CAS Number	12005-57-1;
3D model (JSmol)	Interactive image;
ChemSpider	34998567;
PubChem CID	118856397;
	InChI InChI=1S/14Al.12Ca.33O/q14+3;12+2;33*-2 Key: WAUBKNFRIUQIER-UHFFFAOYSA-N;
	SMILES [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2];
Properties
Chemical formula	Ca12Al14O33
Molar mass	1,386.66 g·mol−1
Appearance	Clear to black solid, depending on synthesis and doping
Density	2.68 g·cm−3
Melting point	1,400 °C (2,550 °F; 1,670 K)
Refractive index (nD)	1.614–1.643
Structure
Crystal structure	Cubic
Space group	I43d
Lattice constant	a = 1.1989 nm
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Dodecacalcium hepta-aluminate (12CaO·7Al₂O₃, Ca₁₂Al₁₄O₃₃ or C₁₂A₇) is an inorganic solid that occurs rarely in nature as the mineral mayenite. It is an important phase in calcium aluminate cements and is an intermediate in the manufacture of Portland cement. Its composition and properties have been the subject of much debate, because of variations in composition that can arise during its high-temperature formation.