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The gross details of the structure appear reasonable.

The structure appears to be unique among OOH compounds, but is the same as that assumed by Af.

The bond angles and distances are all within the expected limits and the volume per oxygen is about normal.

However, the possible absence of a center of symmetry not only moves the hydrogen atom off Af, but also allows the oxygen atoms to become nonequivalent, with Af at Af and Af at Af ( space group Af ), where Af represents the oxygens on one side of the Af layers and Af those on the other side.

However, any oxygen nonequivalence would shorten either the already extremely short Af interlayer distance of 2.55 A or the non-hydrogen-bonded Af interlayer interactions which are already quite short at 2.58 Aj.

Hence it is difficult to conceive of a packing of the atoms in this material in which the oxygen atoms are far from geometrical equivalence.

The only effect of lack of a center would then be to release the hydrogen atoms to occupy general, rather than special, positions along the ( 111 ) axis.