2,4,8,10-Tetraoxa-3,9-diphosphaspiro(5.5)undecane, 3,9-dimethyl-, 3,9-dioxide 3,9-Dimethyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane 3,9-dioxide 3001-98-7 EINECS 221-088-9 Pentaerythritol spirobis(methylphosphonate)