RbCN₃H₄: The First Structurally Characterized Salt of a New Class of Guanidinate Compounds

Abstract

Rubidium guanidinate, RbCN(3)H(4), was synthesized from guanidine and rubidium hydride, and the crystal structure was determined from powder X-ray diffraction (PXRD) data. RbCN(3)H(4) crystallizes in the orthorhombic space group Pnma (No. 62) with four formula units per cell. The guanidinate anions are arranged in double chains running along the b axis, stacked almost perpendicularly to each other to form a three-dimensional network. The rubidium cations, coordinated by 11 N atoms, occupy the vacancies of the network in a zigzag motif along the b axis. Because the PXRD structure of the CN(3) core clearly indicates the N-atom functionalities and the location of the H-atom positions, the latter spatial parameters were determined from Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) density functional theory calculations. The corresponding ν(NH) stretching modes can be observed in the IR spectrum, and the volume chemistry of RbCN(3)H(4) mirrors the efficient packing of the saltlike phase.

Synthesis, Structure, and Properties of SrC(NH)3, a Nitrogen‐Based Carbonate Analogue with the Trinacria Motif

“…[13,14] À ion. [18] b) ORTEP representation of the guanidine trinacria based on neutron data with thermal ellipsoids set at 50 %probability.Hlies above or below the mirror plane with equal occupancies.…”

RbCN3H4 and CsCN3H4: A Neutron Powder and Single‐­Crystal X‐ray Diffraction Study

“…The temperature (T = 100 K) was controlled using an Oxford Cryostream 700. The structures were solved using the previously known model [1] and refined by fullmatrix least-squares procedures based on F 2 with all measured reflections (SHELXL-97). [5] All non-hydrogen atoms were refined with anisotropic but hydrogen atoms with isotropic displacement parameters.…”

“…[1] Shortly after this study, three more representatives, namely NaCN 3 H 4 (CN 3 H 5 ) 2 , NaCN 3 H 4 , and KCN 3 H 4 , were synthesized and structurally characterized from single-crystal X-ray diffraction (SC-XRD). [2,3] The very first crystal structure of RbCN 3 H 4 was solved from powder X-ray diffraction (P-XRD) data collected at 10 K and revealed the positions of the Rb, C, and N atoms.…”

Synthesis, Crystal Structure, Polymorphism, and Magnetism of Eu(CN3H4)2 and First Evidence of EuC(NH)3

“…Inorganics 2017, 5, 10 2 of 14 molecule (Figure 1), demonstrated by the preparation of the alkali-metal guanidinates [27][28][29].…”

“…In the gas phase, the most stable conformation was calculated as the syn-conformation [35], adopted in the solid state in KCN3H4, RbCN3H4, and CsCN3H4 [27,28,41]. The energetically less favorable anti-conformation is adopted in LiCN3H4 and NaCN3H4, owing presumably to improved packing and hydrogen-bonding [28,29].…”