76791
In the thermodynamically stable room-temperature form , α-quartz , these tetrahedra are linked in intertwined helical chains with two different Si–O distances ( 159.7 and 161.7 " pm ) with a Si–O–Si angle of 144 ° .
 location: Si–O–Si
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Si–O–Si 
Answer:
 location: Si–O–Si