Antimony Sulphide
Definition
Sb2S3, the primary fuel in conventional primer formulations, burning rapidly in the presence of oxygen released by barium nitrate during ignition.
- Formula
- Sb2S3
- Role
- Primary fuel in conventional primer formulations
- Oxidiser partner
- Barium nitrate, releases oxygen for combustion
- Relevance
- One of the three key elements detected in GSR SEM-EDX analysis
Common questions
Why is antimony sulphide specifically important to gunshot residue analysis?+
Its combustion, together with barium and lead from the oxidiser and primer, produces the characteristic spheroidal particles that SEM-EDX searches for, so detecting antimony alongside barium and lead in a fused particle is a strong indicator of primer discharge rather than an unrelated environmental source.
Does every firearm primer contain antimony sulphide?+
No. Some modern lead-free or heavy-metal-free primer formulations replace antimony sulphide and lead styphnate with alternative fuels and oxidisers, which is why GSR examiners also look for particle morphology and elemental combinations beyond the classic lead-barium-antimony signature.
Related terms
- ASTM E1588
- ASTM International standard practice for gunshot residue analysis by scanning electron microscopy with energy-dispersive spectrometry. Defines particle classification (characteristic, consistent-with, indicative), morphology...
- Automated Particle Search (APS)
- A software-driven SEM mode that scans the entire stub surface using backscattered electron contrast, flags particles above an atomic-number threshold, and triggers...
- Barium Nitrate
- Ba(NO3)2, the oxidiser in conventional primer formulations, decomposing thermally to release molecular oxygen that sustains the combustion of antimony sulphide fuel.
- Characteristic Particle
- ASTM E1588 category: a single particle in which Pb, Sb, and Ba are simultaneously detected by EDS, with morphology consistent with melt-and-quench...
- Consistent Particle
- ASTM E1588 category: a particle containing two of the three primer elements (Pb-Sb, Pb-Ba, or Sb-Ba), or all three elements without spherical...
- ENFSI EWG-GSR
- The European Network of Forensic Science Institutes Expert Working Group on Gunshot Residue. Produces best-practice manuals, proficiency test rounds, and guidance on...
- Lead Styphnate
- Lead trinitroresorcinate (Pb(C6H(NO2)3O2)), the primary explosive in conventional primer compounds. Co-oxidised with barium nitrate and antimony sulfide to produce the Pb-Ba-Sb triad...
- Melt-and-Quench Mechanism
- The physical process by which GSR particles form: primer components are vaporised at firing temperatures, condense into spherical droplets in the expanding...
- Secondary Transfer
- The movement of a glass fragment from a primary surface (which contacted the broken glass) to a secondary surface (which contacted the...