Problems for atom position with 1 2 H 0 396 0 038 0

HP 2015-02-04

Hi, all

Does anybody have the experience to build crystal structure using Materials Studio 4.4?

We try to use the CASTEP nested in this software. It is convenient for us to build general structure in MS.

Our question is: the structure we build as 01.xsd looks like wrong, because extraneous hydrogen atoms occurs in the interlayer between the double aluminum layers. There are more hydrogen atoms up to 8 H atoms in the unit cell. The net charge after adding hydrogen is +4. It should be zero, and should be only 4 AlOOH units in the cell. I am wondering if Materials Studio can hide 50% hydrogen through setting the occupancy by 0.5.

The problem may be in the occupancy of hydrogen. I have already changed the occupancy of hydrogen to 0.5 during building the crystal. However, all the hydrogen atoms always displayed in the unit cell. It looks like a wrong structure. How can I make the hydrogen atoms just show 1/2?

The cell parameters is in the following list:
Space group: 63-amam,a=3.693,b=12.22,c=2.865;
Atom positions: Al (0.25,-0.3178,0),O1( 0.25,0.2897,0),O2(0.25, 0.0809,0),1/2 H (0.396,0.038,0).
Structure refs: Clays and clay Minerals, 1981, 29(6):435-445.

I hope I can get a structure similar to 02.xsd but not the present 02.xsd, if i can hide 1/2 H atoms in 01.xsd. Now, the present 02.xsd is obtained by changing H position to (0.25,0.5,0.5), not the right positon at (0.396,0.038,0). For 02.xsd, the hydrogen bond appeared and no redundant hydrogen occurs, but it is not right absolutely due to the wrong hydrogen position at (0.25,0.5,0.5) . I think i can not optimize the bulk structure unit cell based on the present 02.xsd. How can i get the right structure for boehmite? I need your help, please.

PS, I am out for several month and still waiting for my company's MS license number to get the help from accelry company.

Thanks for your any comments

Leo