<|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:
3.5 3.5 6.8
90 90 90
Sr
0.00 0.00 0.00
Nb
0.00 0.00 0.38
Si
0.73 0.73 0.59
Si
0.73 0.73 0.17
Identify the crystal system.<|im_end|>
<|im_start|>assistant
Given the following crystal representation:
3.5 3.5 6.8
90 90 90
Sr
0.00 0.00 0.00
Nb
0.00 0.00 0.38
Si
0.73 0.73 0.59
Si
0.73 0.73 0.17
Identify the crystal system.