Ammonothermal Synthesis, Crystal Structure, and Vibrational Properties of the Doubly Deprotonated Calcium Guanidinate, CaC(NH)₃

Abstract

We report the synthesis of the doubly deprotonated calcium guanidinate, CaC(NH)3, from liquid ammonia and its crystal structure as determined from powder X‐ray and neutron diffraction, and confirmed using CNH elemental analysis and infrared (IR) spectroscopy data. CaC(NH)3 crystallizes in the hexagonal system with space group P63/m (no. 176) with Z = 2 and a = 5.2666(13) Å, c = 6.5881(6) Å and V = 158.25(4) Å3. We also compare the structural similarities and differences of this phase with the isotypical strontium and ytterbium compounds.

Stabilization of Guanidinate Anions [CN3]5− in Calcite‐Type SbCN3

“…A straightforward approach to synthesizing guanidinates involves the deprotonation of guanidine, which can be performed by strong bases like alkali metal hydrides or amides (Table S1) [16–24] . This method allowed achieving the double‐deprotonated guanidinates with the chemical formula MC(NH) 3 (M=Ca, Ba, Sr, Eu, Yb) [17,20,24,25] .…”

“…[16][17][18][19][20][21][22][23][24] This method allowed achieving the double-deprotonated guanidinates with the chemical formula MC(NH) 3 (M=Ca, Ba, Sr, Eu, Yb). [17,20,24,25] However, achieving full deprotonation of guanidine proves impossible due to guanidine's inherent properties as a very strong base itself.…”

“…[13][14][15] A straightforward approach to synthesizing guanidinates involves the deprotonation of guanidine, which can be performed by strong bases like alkali metal hydrides or amides (Table S1). [16][17][18][19][20][21][22][23][24] This method allowed achieving the double-deprotonated guanidinates with the chemical formula MC(NH) 3 (M=Ca, Ba, Sr, Eu, Yb). [17,20,24,25] However, achieving full deprotonation of guanidine proves impossible due to guanidine's inherent properties as a very strong base itself.…”