1	C6J	2-(2,2-diphosphonoethyl)-1-methylpyridin-1-ium	1.000
2	C6M	2-(2,2-diphosphonoethyl)-1-propylpyridin-1-ium	0.895
3	RIS	1-hydroxy-2-(3-pyridinyl)ethylidene bis-phosphonic acid	0.700