In the lanthanide series , how many members must there be ?
Ln ( Cl ) 3 + 3 HMDS + 3 nBuLi → Ln ( hmds ) 3 + 3 LiCl + 3 butane ( Ln = La , Ce , Pr , Nd , Sm , Eu , Gd , Ho , Yb , and Lu ) Silylamides are important as starting materials in lanthanide chemistry , as lanthanide chlorides have either poor solubility or poor stability in common solvents .