<|im_start|>system
Please reason step by step, and put your final answer within \boxed{}.<|im_end|>
<|im_start|>user
Given the following crystal representation:
7.4 7.4 7.4
154 139 48
Mg
0.00 0.00 0.00
Nb
0.00 0.00 0.77
Br
0.61 0.00 0.65
Br
0.00 0.58 0.12
Identify the crystal system.<|im_end|>
<|im_start|>assistant
Given the following crystal representation:
7.4 7.4 7.4
154 139 48
Mg
0.00 0.00 0.00
Nb
0.00 0.00 0.77
Br
0.61 0.00 0.65
Br
0.00 0.58 0.12
Identify the crystal system.