Open-Framework Cobalt (II) Phosphates with Sodalite-Related Architectures

Abstract

Three new framework cobalt (II) phosphates have been synthesized hydrothermally in the presence of piperazine as a structure-directing agent. Crystal data: compound I, [C4N2H12][Co(HPO4)2], monoclinic space group=P21/n 001(no. 14), a=8.5521(10) Å, b=13.5791(15) Å, c=10.0405(11) Å, β=96.855(2)°, V=1157.7(2) Å3, Z=4, M=339.04, Dc= 1.945 g m−3, MoKα, λ=0.71073 Å, R1(F0)=0.053; compound II, [C4N2H11][Co2(PO4)(H2PO4)2], monoclinic space group=C2/c (no. 15), a=13.444(5) Å, b=12.874(5) Å, c=8.224(2) Å, β=94.64(2)°, V=1418.8 (2)A 3, Z=8, M=494.96, Dc=2.317 g cm−3, MoKα, λ=0.71073 Å ,R1(F0)=0.047; compound III, [C4N2H12]2[Co4(HPO4)6], monoclinic space group=P21/c (no. 14) a=12.8780(13) Å, b=26.671(3) Å, c=8.2592(8) Å, β=96.931(2)°, V=2816.0(5) Å3, Z=4, M=987.90, Dc=2.330gcm–3, MoKα, λ=0.71073 Å, R1(F0)=0.048. The structure of I consists of one-dimensional chains built up of corner-shared four rings (Co2P2) which are key structural units that form the sodalite cage. Compounds II and III have interrupted sodalite-type structures resulting from the removal of Co2+ atoms from sites related by two-fold axes passing through the four rings of the normal sodalite cage structure. The modes of the interruptions in II and III differ in relation to the structure of a regular sodalite cage.