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BrCl crystallizes in the orthorhombic Cmc2_1 space group. The structure is one-dimensional and consists of two BrCl ribbons oriented in the (0, 0, 1) direction. Br is bonded in a linear geometry to two equivalent Cl atoms. There are one shorter (2.41 Å) and one longer (2.42 Å) Br–Cl bond lengths. Cl is bonded in a water-like geometry to two equivalent Br atoms.
BrCl is alpha carbon monoxide-like structured and crystallizes in the hexagonal P6_3mc space group. The structure is zero-dimensional and consists of two bromine chloride molecules. Br is bonded in a single-bond geometry to one Cl atom. The Br–Cl bond length is 2.17 Å. Cl is bonded in a single-bond geometry to one Br atom.
Rb2CuCl2Br2 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. Rb1+ is bonded in a 9-coordinate geometry to five equivalent Br1- and four equivalent Cl1- atoms. There are a spread of Rb–Br bond distances ranging from 3.52–3.68 Å. All Rb–Cl bond lengths are 3.41 Å. Cu2+ is bonded to two equivalent Br1- and four equivalent Cl1- atoms to form corner-sharing CuBr2Cl4 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Cu–Br bond lengths are 2.56 Å. There are two shorter (2.26 Å) and two longer (2.91 Å) Cu–Cl bond lengths. Br1- is bonded in a 6-coordinate geometry to five equivalent Rb1+ and one Cu2+ atom. Cl1- is bonded in a 6-coordinate geometry to four equivalent Rb1+ and two equivalent Cu2+ atoms.
Rb2CrCl2Br2 is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a distorted q6 geometry to five equivalent Br1- and four equivalent Cl1- atoms. There are four shorter (3.61 Å) and one longer (3.63 Å) Rb–Br bond lengths. All Rb–Cl bond lengths are 3.45 Å. Cr2+ is bonded to two equivalent Br1- and four equivalent Cl1- atoms to form corner-sharing CrBr2Cl4 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Cr–Br bond lengths are 2.63 Å. All Cr–Cl bond lengths are 2.54 Å. Br1- is bonded to five equivalent Rb1+ and one Cr2+ atom to form distorted BrRb5Cr octahedra that share corners with five equivalent BrRb5Cr octahedra, corners with twelve equivalent ClRb4Cr2 octahedra, edges with eight equivalent BrRb5Cr octahedra, and faces with four equivalent ClRb4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°. Cl1- is bonded to four equivalent Rb1+ and two equivalent Cr2+ atoms to form distorted ClRb4Cr2 octahedra that share corners with two equivalent ClRb4Cr2 octahedra, corners with twelve equivalent BrRb5Cr octahedra, edges with two equivalent ClRb4Cr2 octahedra, faces with four equivalent BrRb5Cr octahedra, and faces with four equivalent ClRb4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°.
Rb2CrCl2Br2 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. Rb1+ is bonded in a distorted q6 geometry to five equivalent Br1- and four equivalent Cl1- atoms. There are one shorter (3.62 Å) and four longer (3.64 Å) Rb–Br bond lengths. There are two shorter (3.45 Å) and two longer (3.46 Å) Rb–Cl bond lengths. Cr2+ is bonded to two equivalent Br1- and four equivalent Cl1- atoms to form corner-sharing CrBr2Cl4 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Cr–Br bond lengths are 2.62 Å. There are two shorter (2.46 Å) and two longer (2.67 Å) Cr–Cl bond lengths. Br1- is bonded to five equivalent Rb1+ and one Cr2+ atom to form distorted BrRb5Cr octahedra that share corners with five equivalent BrRb5Cr octahedra, corners with twelve equivalent ClRb4Cr2 octahedra, edges with eight equivalent BrRb5Cr octahedra, and faces with four equivalent ClRb4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 0–56°. Cl1- is bonded to four equivalent Rb1+ and two equivalent Cr2+ atoms to form distorted ClRb4Cr2 octahedra that share corners with two equivalent ClRb4Cr2 octahedra, corners with twelve equivalent BrRb5Cr octahedra, edges with two equivalent ClRb4Cr2 octahedra, faces with four equivalent BrRb5Cr octahedra, and faces with four equivalent ClRb4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 0–56°.
We report aircraft observations of extreme levels of HCl and the dihalogens Cl 2 , Br 2 , and BrCl in an industrial plume near the Great Salt Lake, Utah. Complete depletion of O 3 was observed concurrently with halogen enhancements as a direct result of photochemically produced halogen radicals. Observed fluxes for Cl 2 , HCl, and NO x agreed with facility-reported emissions inventories. Bromine emissions are not required to be reported in the inventory, but are estimated as 173 Mg year –1 Br 2 and 949 Mg year –1 BrCl, representing a major uncounted oxidant source. A zero-dimensional photochemical box model reproduced the observed O 3 depletions and demonstrated that bromine radical cycling was principally responsible for the rapid O 3 depletion. Inclusion of observed halogen emissions in both the box model and a 3D chemical model showed significant increases in oxidants and particulate matter (PM 2.5 ) in the populated regions of the Great Salt Lake Basin, where winter PM 2.5 is among the most severe air quality issues in the U.S. The model shows regional PM 2.5 increases of 10%–25% attributable to this single industrial halogen source, demonstrating the impact of underreported industrial bromine emissions on oxidation sources and air quality within a major urban area of the western U.S.
All inorganic cesium lead trihalide nanocrystals are promising light emitters for bright light emitting diodes (LEDs). Here we demonstrate CsPb(BrCl) 1.5 nanocrystals in metal-organic frameworks (MOF) thin films to achieve bright and stable blue LEDs. The lead metal nodes in the MOF thin film react with Cs-halide salts, resulting in 10~20 nm nanocrystals. This is revealed by X-ray scattering and transmission electron microscopy. Employing the CsPbX 3 - MOF thin films as emission layers, bright deep blue and sky-blue LEDs are demonstrated that emit at 452 nm and 476 nm respectively. The maximum external quantum efficiencies of these devices are 0.72% for deep blue LEDs and 5.6% for sky blue LEDs. More importantly, the device can maintain 50% of its original electroluminescence (T 50 ) for 2.23 hours when driving at 4.2V. Detailed optical spectroscopy and time-of-flight secondary ion mass spectroscopy suggest that the ion migration can be suppressed that maintains the emission brightness and spectra. Our study provides a new route for fabricating stable blue light emitting diodes with all-inorganic perovskite nanocrystals.