Syntheses, Crystal Structures, and Thermal Behaviors of Two New Metallo‐Organically Templated Pentaborates

Two new cadmium borates, [Cd(en) 3 ][B 5 O 6 (OH) 4 ] 2 · 2H 2 O (en = ethylenediamine) ( 1 ) and [Cd(DETA) 2 ][B 5 O 6 (OH) 4 ] 2 (DETA = diethylenetriamine) ( 2 ) were synthesized in a novel procedure under mild solvothermal conditions and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, elemental analysis, and TG–DTA. The compound 1 crystallizes in monoclinic system, space group P 2 1 / c (No. 14) with a = 8.526(2) Å, b = 23.127(6) Å, c = 15.438(4) Å, β = 94.320(3) °, V = 3035.5(13) Å 3 , Z = 4. Compound 2 is triclinic, space group P $\bar{1}$ (No. 2), a = 8.632(5) Å, b = 9.418(6) Å, c = 27.856(18) Å, α = 95.415(8) °, β = 91.891(7) °, γ = 93.563 (7) °, V = 2248(2) Å 3 , Z = 3. The anionic units of the both structures, [B 5 O 6 (OH) 4 ] – are linked by hydrogen bonds to form a three‐dimensional framework with large channels, in which the templating cadmium complex cations are located. The thermal decomposition performance of compound 1 requires three steps, whereas only two steps are needed for compound 2 , which all lead to amorphous phases. These processes are well explained considering the structure and the change in the Cd 2+ coordination during heating.