Other AFm phases containing aluminium

The range of anions that can occupy the X positions is very wide (A11,D20) even anions that form calcium salts of very low solubility, such as ffuoride, can be introduced using special techniques. We shall consider only those most relevant to cement chemistry. Tables 6.2 and 6.3 include data. C3A CaCl2 l0H2O or [Ca2Al(0H)g]Cl-2H20 (Friedel s salt) can be formed in concrete exposed to chloride solutions. Two polytypes are known p is the 

C2A8H8, known by its mineral name of stratlingite and also as gehlenite hydrate , is well established as a natural mineral, hydration product of i certain types of composite cements and laboratory product. Its crystal data 

Naturally occurring AFm phases, called hydrocalumite. appear to vary in composition. The original specimen was reported to have a composition near to C AHij with some CO 3 and a monoclinic unit cell similar to that of a-CjA CaClj-lOHjO (T31), but others have proved to be either the a or the p polymorph of that compound or members of a CjA CaCl2 l0H2O-C4AH,3 solid solution series (F26). 

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