PM space group and CM space

[jlwindy]

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]

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

[jlwindy]

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.

Thanks for your reply
Best wishes.

[ebousquet]

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]

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.

Thanks for your reply.

[ebousquet]

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]

Dear eric
Thanks for your suggest.l will read it.

Best wishes.
jlwindy