organic radical, M is a metal or metalloid selected from {TAIL ~ antimony}, arsenic, {HEAD ~ phosphorus} and boron, and d is an integer equal to from 4 6 L inclusive 
organic radical , M is a metal or metalloid selected from { TAIL ~ antimony } , arsenic , { HEAD ~ phosphorus } and boron , and d is an integer equal to from 4 6 L inclusive
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH