Lead(II) Bromide CAS 10031-22-8

Introduction to Lead(II) Bromide

Lead(II) Bromide is a white crystalline powder, an inorganic lead halide with an orthorhombic PbBr₂ lattice and a density of 6.66 g/cm³. Water solubility is slight at 20 °C (~0.5 g/100 mL) but quadruples near boiling, so hot-water recrystallisation purifies the salt without organic solvents. It functions as the lead source for halide perovskite semiconductors and as a bromide building block in fine-chemical synthesis.

The optoelectronic grade holds total trace metals below 10 ppm by ICP-MS, keeping Fe, Cu, and Na low enough to preserve CsPbBr₃ photoluminescence quantum yield. One practical caution: PbBr₂ dissolves sharply in excess bromide, forming soluble [PbBr₄]²⁻ complexes. Washing a filtered cake with KBr or NH₄Br solution instead of cold deionised water silently dissolves 5–10% of the batch.

Key Features of Lead(II) Bromide

• Stoichiometric perovskite precursor. Reacts 1:1 molar with CsBr or CH₃NH₃Br in DMF/DMSO to give phase-pure CsPbBr₃ or MAPbBr₃; a Br:Pb ratio of 2.00 ± 0.02 prevents mixed-halide side phases.
• Recrystallisation-friendly solubility curve. ~0.5 g/100 mL at 20 °C versus ~2 g/100 mL at 100 °C—a single hot-water pass lifts assay from 98% to >99.9% with no organic solvent waste.
• High photon stopping power. Pb (Z = 82) at 6.66 g/cm³ delivers strong X-ray and γ-ray attenuation, suiting scintillator host crystals and radiation-shielding glass research.
• Polybromide complexation. Freely soluble in concentrated HBr, NH₄Br, and KBr solutions as [PbBr₄]²⁻, enabling solution crystal growth and controlled re-precipitation processes.
• Low hygroscopicity. Unlike hydrated lead salts that cake in humid warehouses, PbBr₂ powder stays free-flowing at 70% RH; only light-tight storage is needed to prevent slight grey tinting.

Lead(II) Bromide Chemical & Physical Properties

Applications of Lead(II) Bromide

Halide perovskite solar cells and LEDs: Co-dissolved with CsBr or MABr at 1:1 molar ratio (40–50 wt% in 4:1 DMF:DMSO), spin-coated and annealed at 80–100 °C. Optoelectronic grade (99.99%) yields CsPbBr₃ films with PLQY >80%; standard grade suits two-step sequential deposition.

CsPbBr₃ quantum dots for displays: Injected into hot (140–180 °C) oleic acid/oleylamine/1-octadecene together with cesium oleate. The PbBr₂ feed controls nanocrystal edge length at 8–12 nm and green emission at 510–520 nm.

Scintillator and X-ray detector crystals: Melt-grown by Bridgman–Stockbarger above the 373 °C melting point, or grown from aqueous anti-solvent systems. The high effective Z gives strong γ-ray stopping power for photon-counting detectors.

Fine-chemical and laboratory reagent: Bromide/lead source for lead-mediated organic transformations, precursor for other lead halides, and analytical reagent. Typical charge: 0.5–5% w/w of reaction mass.

Storage & Safety Precautions for Lead(II) Bromide

Storage conditions. Store in sealed, PE-lined bags on pallets at 5–30 °C, dry and away from light—prolonged light exposure may cause a slight grey tint without affecting assay. Keep in a dedicated toxic-materials area, separated from foodstuffs, strong acids (which can liberate HBr fumes), and strong oxidisers.

Safety and PPE. GHS: Repr. 1A (H360Df); Acute Tox. 4 (H302, H332); STOT RE 2 (H373); Aquatic Acute/Chronic 1 (H400, H410). Wear a P3 particulate respirator, nitrile gloves, and goggles; no eating or drinking in the handling area; wash hands after handling. Spills: wet-mop or HEPA-vacuum to avoid dust; dispose as hazardous lead waste—never flush to drain.

Transport classification. Class 6.1, Packing Group III, UN 3288 (Toxic solid, inorganic, n.o.s.); marine pollutant. DG declaration required for ocean and air freight.

Practitioner note: For incoming QC, assay lead by EDTA complexometric titration at pH 5–6 with xylenol orange indicator; check chloride by ion chromatography—tap-water wash residue shows Cl⁻ >200 ppm and degrades perovskite film morphology. For optoelectronic grade, run ICP-MS (Na, K, Fe, Cu) and reject if the total exceeds 10 ppm.

Lead(II) Bromide FAQ

Q: Is Lead(II) Bromide (CAS 10031-22-8) pure enough for perovskite solar cells, or only for industrial use?

A: Both grades ship from this line. The ≥98% industrial grade suits two-step sequential deposition and crystal-growth work; the 99.99% optoelectronic grade holds total trace metals <10 ppm (ICP-MS) and Cl⁻ <50 ppm for one-step antisolvent processes targeting PLQY >80%. State the target application on the PO so QC releases the correct spec.

Q: Why did I lose 8% of my batch when washing the filter cake with ammonium bromide solution?

A: PbBr₂ forms soluble polybromide complexes ([PbBr₄]²) in excess Br⁻. NH₄Br, KBr, or HBr wash liquors re-dissolve the cake. Wash only with cold (5–10 °C) deionised water in 2–3 small portions; the ~0.45 g/100 mL cold-water solubility keeps wash loss below 1%.

Q: Can PbBr₂ be recrystallised from hot water without hydrolysis?

A: Yes. Dissolve at 90–100 °C (~2 g/100 mL), add 1–2 drops of dilute HBr per litre to suppress basic-salt formation, filter hot, then cool to 5–10 °C. Colorless needle crystals form; one pass lifts assay from 98% to >99.9%. Dry at 105 °C for 2 h and store light-tight.