Re: [Spglib-users] [SPAM] Re: why alpha, beta, gamma all equals 90 degree gives monoclinic symmetry?

[Atsushi T. <atz...@gm...>]

You can read International tables for crystallography volume A.
I have nothing to say more.

Togo

On Tue, Nov 7, 2017 at 5:54 PM, balabi <ba...@qq...> wrote:
> Dear Togo,
>     Thank you so much for quick reply.
>     You got me confused. But according to wiki page
> https://en.wikipedia.org/wiki/List_of_space_groups#List_of_Monoclinic
>     The graph clearly shows that monoclinic group has beta≠90. So I thought
> this should imply that if beta=90, then the group can not be monoclinic.
>     I really don't know what is wrong with my logic?
>
> best regards
>
> On 11/7/2017 16:39，Atsushi Togo<atz...@gm...> wrote：
>
> Hi,
>
> Do you think if the lattice is orthorhombic, the space group type has
> to be of orthorhombic? I don't think so.
>
> Togo
>
> On Tue, Nov 7, 2017 at 5:29 PM, balabi <ba...@qq...> wrote:
>> Dear developers,
>>     I have a WTe2 monolayer structure which has alpha,beta,gamma all
>> equals
>> 90 degree. However, spglib gives space group 6, which is monoclinic. As
>> far
>> as I know, monoclinic has one angle not equal to 90 degree. So how could
>> it
>> be possible?
>>
>>     below is script
>>
>> import sys
>> import numpy as np
>> import spglib
>> test_cell=(np.array([[  6.24900000000000e+00,   0.00000000000000e+00,
>>            0.00000000000000e+00],
>>         [  0.00000000000000e+00,   3.47700000000000e+00,
>>            0.00000000000000e+00],
>>         [ 0,   0.00000000000000e+00,
>>            1.91998000000000e+01]]), np.array([[ 0.65606 ,  0.5     ,
>> 0.392155],
>>         [ 0.15039 ,  0.      ,  0.424309],
>>         [ 0.00392 ,  0.5     ,  0.575625],
>>         [ 0.5     ,  0.      ,  0.607845],
>>         [ 0.75699 ,  0.      ,  0.494495],
>>         [ 0.39741 ,  0.5     ,  0.505607]]), np.array([52, 52, 52, 52, 74,
>> 74]))
>> spglib.get_symmetry_dataset(test_cell,symprec=0.01)
>>
>> Is it a bug?
>>
>> best regards
>>
>>
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>
>
>
> --
> Atsushi Togo
> Elements Strategy Initiative for Structural Materials, Kyoto university
> E-mail: atz...@gm...
>
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-- 
Atsushi Togo
Elements Strategy Initiative for Structural Materials, Kyoto university
E-mail: atz...@gm...