Element · Br

Bromine

The only non-metallic element that is liquid at room temperature, and an industrial workhorse whose main use has been regulated away twice.

Bromine is a dense, deep red-brown liquid that gives off a choking vapour at room temperature — the name comes from the Greek for stench. It is extracted from brine, particularly from the Dead Sea and from deep underground deposits, rather than mined as a solid.

Its industrial history is one of repeated substitution. Bromine compounds were once added to leaded petrol to scavenge lead deposits from engines; that use ended with leaded fuel. Brominated flame retardants then became the dominant application, and several of those have since been restricted over concerns about persistence and bioaccumulation.

Uses

Flame retardants remain the largest use, in plastics, electronics housings and textiles, though the specific compounds in use have changed considerably under regulatory pressure.

Bromine also makes drilling fluids dense enough to control well pressure, serves as a biocide in cooling water and pools where chlorine is unsuitable, and appears in pharmaceutical synthesis. Silver bromide was central to photographic film, a use that has largely disappeared. Zinc-bromine flow batteries are a candidate for grid storage.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is used as

Flame retardancy — application · brominated flame retardants became the dominant use, and several have since been restricted

is produced by

Brine evaporation — process · concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element

is found in

Seawater — material · at sixty-five parts per million, which is dilute and still the source of most of the world's bromine

is sourced from

Seawater — material · displaced from concentrated seawater and from the connate brines pumped out of oil wells, which are richer

Sources

Material World
Our own writing
Wikidata
Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
PubChem
US National Library of Medicine · Mixed — aggregated third-party content, rights retained by depositors
NIST — National Institute of Standards and Technology
United States Department of Commerce · US Government work — public information, credit requested

Questions this page answers

Where it comes from, and what it becomes

Follow Bromine back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

Bromine → is produced by (concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element) → Brine evaporation → takes as input (and the pond sequence is run so that the less soluble salts crystallise out first, leaving the sodium chloride to be harvested on its own) → Salt → is sourced from (mined as rock salt from bedded deposits, or dissolved in place and pumped up as brine — which is what the chemical industry wants anyway) → Evaporite → is sourced from (what is left when a body of seawater evaporates faster than it is replenished — the salts come out in order of solubility, which is why the sequence is readable) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
Bromine → is sourced from (displaced from concentrated seawater and from the connate brines pumped out of oil wells, which are richer) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
Bromine → is produced by (concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element) → Brine evaporation → takes as input (the feedstock for solar salt and, in the salars, for the far stronger brines that lithium comes from) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
Bromine → is produced by (concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element) → Brine evaporation → takes as input (and the pond sequence is run so that the less soluble salts crystallise out first, leaving the sodium chloride to be harvested on its own) → Salt → is sourced from (by solar evaporation, which needs a dry sunny coast and is the cheapest route there is) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
Bromine → is produced by (concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element) → Brine evaporation → takes as input (and the pond sequence is run so that the less soluble salts crystallise out first, leaving the sodium chloride to be harvested on its own) → Salt → is sourced from (mined as rock salt from bedded deposits, or dissolved in place and pumped up as brine — which is what the chemical industry wants anyway) → Evaporite → is composed of (precipitated early, when the water has reduced to roughly a fifth of its volume) → Gypsum
Bromine → is produced by (concentrated by evaporation and then displaced from solution with chlorine, because bromine is wanted as the element) → Brine evaporation → takes as input (and the pond sequence is run so that the less soluble salts crystallise out first, leaving the sodium chloride to be harvested on its own) → Salt → is sourced from (mined as rock salt from bedded deposits, or dissolved in place and pumped up as brine — which is what the chemical industry wants anyway) → Evaporite → is composed of (the bulk of most evaporite sequences, and the reason the rock is called salt) → Halite

These are the most distinct paths back. Bromine can be traced through others besides.

Downstream — what it becomes

Bromine → is used as (brominated flame retardants became the dominant use, and several have since been restricted) → Flame retardancy