1 research outputs found
Ammonothermal Synthesis, Crystal Structure, and Properties of the Ytterbium(II) and Ytterbium(III) Amides and the First Two Rare-Earth-Metal Guanidinates, YbC(NH)<sub>3</sub> and Yb(CN<sub>3</sub>H<sub>4</sub>)<sub>3</sub>
We
report the oxidation-controlled synthesis of the ytterbium amides
YbÂ(NH<sub>2</sub>)<sub>2</sub> and YbÂ(NH<sub>2</sub>)<sub>3</sub> and
the first rare-earth-metal guanidinates YbCÂ(NH)<sub>3</sub> and YbÂ(CN<sub>3</sub>H<sub>4</sub>)<sub>3</sub> from liquid ammonia. For YbÂ(NH<sub>2</sub>)<sub>2</sub>, we present experimental atomic displacement
parameters from powder X-ray diffraction (PXRD) and density functional
theory (DFT)-derived hydrogen positions for the first time. For YbÂ(NH<sub>2</sub>)<sub>3</sub>, the indexing proposal based on PXRD arrives
at <i>R</i>3Ì…, <i>a</i> = 6.2477(2) Ã…, <i>c</i> = 17.132(1) Ã…, <i>V</i> = 579.15(4) Ã…<sup>3</sup>, and <i>Z</i> = 6. The oxidation-controlled synthesis
was also applied to make the first rare-earth guanidinates, namely,
the doubly deprotonated YbCÂ(NH)<sub>3</sub> and the singly deprotonated
YbÂ(CN<sub>3</sub>H<sub>4</sub>)<sub>3</sub>. YbCÂ(NH)<sub>3</sub> is
isostructural with SrCÂ(NH)<sub>3</sub>, as derived from PXRD (<i>P</i>6<sub>3</sub>/<i>m</i>, <i>a</i> =
5.2596(2) Ã…, <i>c</i> = 6.6704(2) Ã…, <i>V</i> = 159.81(1) Ã…<sup>3</sup>, and <i>Z</i> = 2). YbÂ(CN<sub>3</sub>H<sub>4</sub>)<sub>3</sub> crystallizes in a structure derived
from the [ReO<sub>3</sub>] type, as studied by powder neutron diffraction
(<i>Pn</i>3Ì…, <i>a</i> = 13.5307(3) Ã…, <i>V</i> = 2477.22(8) Ã…<sup>3</sup>, and <i>Z</i> = 8 at 10 K). Electrostatic and hydrogen-bonding interactions cooperate
to stabilize the structure with wide and empty channels. The IR spectra
of the guanidinates are compared with DFT-calculated phonon spectra
to identify the vibrational modes. SQUID magnetometry shows that YbÂ(CN<sub>3</sub>H<sub>4</sub>)<sub>3</sub> is a paramagnet with isolated Yb<sup>3+</sup> (4f<sup>13</sup>) ions. A <i>CONDON 2.0</i> fit
was used to extract all relevant parameters