Li4Na2CsB7O14: a new edge-sharing [BO4]5− tetrahedra containing borate with high anisotropic thermal expansion

Li4Na2CsB7O14 with unique edge-sharing [BO4]5- tetrahedra, an unprecedented [B14O28]14- cluster, and high anisotropic thermal expansion has been obtained under atmospheric pressure conditions, indicating that high pressure is not essential for obtaining edge-sharing [BO4]5- tetrahedra-containing borates. In addition, Li4Na2CsB7O14 may be used as a thermal expansion material.