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