Sunlight can be used to split water into hydrogen and oxygen by means of a photoelectrochemical (PEC) cell. Oxide nanostructures in heterojunction geometry, consisting of anisotropic WO 3 nanostructures coated with a second semiconductor having a narrower band gap, such as α-Fe 2 O 3 , have emerged as prospective photoanodes. Herein, the integration of monodisperse CoPd nanocrystals (NCs) with α-Fe 2 O 3 and WO 3 /α-Fe 2 O 3 heterojunction semiconductor nanostructures for PEC water oxidation is reported. Depositing CoPd NCs on the [a]

We report the crystal structure of Ba(CN 3 H 4 ) 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 b 2, a necessity of hydrogen bonding. At 300 K, barium guanidinate crystallizes in P 2 1 / 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 the data‐to‐parameter ratio, anisotropic displacement parameters from first‐principles theory were incorporated in the neutron refinement. Given the correct structural model, the positional parameters of the heavy atoms were also refinable from X‐ray diffraction of a twinned crystal. The two independent guanidinate anions adopt the all‐ trans ‐ and the anti ‐shape. The Ba cation is coordinated by eight imino nitrogens in a square antiprism with Ba−N contacts between 2.81 and 3.04 Å. The IR and Raman spectra of barium guanidinate were compared with DFT‐calculated phonon spectra to identify the vibrational modes.

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.