[2] In Portland cement kilns, C12A7 is an early reaction product of aluminium and calcium oxides in the temperature range 900–1200 °C.

With the onset of melt-phases at higher temperatures, it reacts with further calcium oxide to form tricalcium aluminate.

The unit cell consists of 12 cages with the inner diameter of 0.44 nm and a formal charge of +1/3, two of them host free O2− ions (not shown in the infobox structure).

Studies of the system have shown that the solid solution series extends also to the accommodation of other species in place of the hydroxyl group, including halides, sulfide and oxide ions.

Because of its higher reactivity, leading to excessively rapid hydration, aluminous cements contain relatively low amounts of dodecacalcium hepta-aluminate, or none at all.

[9][10] While undoped C12A7 is a wide-bandgap insulator, electron-doped electride C12A7:e− is a metallic conductor with a conductivity reaching 1500 S/cm at room temperature; it may even exhibit superconductivity upon cooling to 0.2–0.4 K. C12A7:e− is also a catalyst that has potential applications in the ambient-pressure synthesis of ammonia.