0sp2o8 zsp2o ysp2 xsp2o8 wsp2o
b2o2o a2o2 91o2o8 81o2o 71o2
mbo2 lbo2o8 kbo2o jbo2 ibo2o8
xkn2o8 wkn2o vkn2 ukn2o8 tkn2o
8tm2o 7tm2 6tm2o8 5tm2o 4tm2