Ammonothermal Synthesis, X-Ray and Time-of-Flight Neutron Crystal-Structure Determination, and Vibrational Properties of Barium Guanidinate, Ba(CN₃H₄)₂.

ABSTRACT: We report the crystal structure of Ba(CN₃H₄)₂ as synthesized from liquid ammonia. Structure solution based on X-ray diffraction data suffers from a severe pseudo-tetragonal problem due to extreme scattering contrast, so the true monoclinic symmetry is detectable only from neutron powder diffraction patterns, and structure solution and refinement was greatly aided by density-functional theory. The symmetry lowering is due to slight deviations of the guanidinate anion from the mirror plane in space group P 4‾ b2, a necessity of hydrogen bonding. At 300 K, barium guanidinate crystallizes in P2₁/c with a=6.26439(2) Å, b=16.58527(5) Å, c=6.25960(2) Å, and a monoclinic angle of β=90.000(1)°. To improve t

SUBMITTER: Benz S 

PROVIDER: S-EPMC6417364 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature