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## PM space group and CM space

Moderators: jzwanzig, jolafc

jlwindy
Posts: 32
Joined: Tue Jan 08, 2019 4:11 pm

### PM space group and CM space

hello everybody:

I am sorry to ask the simple qusetion that what's the difference between PM space group and CM space.My xred
xred 0.00 0.00 0.00
0.50 0.00 0.50
0.00 0.50 0.50
0.50 0.50 0.00
0.50 0.50 0.46
How to recompose it to CM space group?

Any help is appreciated,

Thank you very much

ebousquet
Posts: 469
Joined: Tue Apr 19, 2011 11:13 am
Location: University of Liege, Belgium

### Re: PM space group and CM space

Dear jlwindy,
What do you mean by "CM" and "PM" space group, where do you see that?
Best wishes,
Eric

jlwindy
Posts: 32
Joined: Tue Jan 08, 2019 4:11 pm

### Re: PM space group and CM space

Dear ebousquet
l find it from space group chart.The message aslo appears in log.file and out.file.
Triclinic: 1, 2 (a, b, c, alpha, beta, gamma)
Monoclinic: 3-15 (a, b, c, 90, beta, 90)
Orthorhombic: 16-74 (a, b, c, 90, 90, 90)
Tetragonal: 75-142 (a, a, c, 90, 90, 90)
Trigonal: 143-145, 147, 149-154, 156-159, 162-165 (a, a, c, 90, 90, 120)
Rhombohedral: 146, 148, 155, 160-161, 166-167 (a, a, c, 90, 90, 120)
Hexagonal: 168-194 (a, a, c, 90, 90, 120)
Cubic: 195-230 (a, a, a, 90, 90, 90)
The PM space group's serial number is 6.The CM space group is 8.I want to understand the differences from them.

Best wishes.

ebousquet
Posts: 469
Joined: Tue Apr 19, 2011 11:13 am
Location: University of Liege, Belgium

### Re: PM space group and CM space

Dear jlwindy,
I still don't know where you find these "CM" and "PM", to be clear just copy and paste the lines from the output or log files where you have this information.
Regarding the space groups, giving the xred is not enough if you want help on that, you have to give the type of atom and the cell parameters too.
All the best,
Eric

jlwindy
Posts: 32
Joined: Tue Jan 08, 2019 4:11 pm

### Re: PM space group and CM space

dear eric

In log and out file,we can find these massage
acell 7.542 7.642 7.791
angdeg 90.0 90.5 90.0

xred 0.00 0.00 0.00
0.50 0.00 0.50
0.00 0.50 0.50
0.50 0.50 0.00
0.50 0.50 0.46
In out.file, DATASET 1 : space group Pm (# 6); Bravais mP (primitive monocl.

ebousquet
Posts: 469
Joined: Tue Apr 19, 2011 11:13 am
Location: University of Liege, Belgium

### Re: PM space group and CM space

Der jlwindy,
Regarding the different notation for symmetries and space groups, I advise you to read the first chapter of the "International Tables for Crystallography" Volume A to get into these notations.
Best wishes,
Eric

jlwindy
Posts: 32
Joined: Tue Jan 08, 2019 4:11 pm

Dear eric