Bromine is the only nonmetallic element liquid at ordinary room temperature.

Bromine is a liquid nonmetal at ordinary room temperature and pressure.

Its melting point is about −7.2 degrees Celsius and its boiling point about 58.8 degrees Celsius.

These boundaries put temperatures around 20 to 25 degrees comfortably within its liquid range.

At ordinary room temperature and atmospheric pressure, bromine is a reddish-brown liquid. Among nonmetallic elements, that combination is unique under those conditions. The qualification matters because “room temperature” is not an exact scientific constant. Bromine melts near minus 7.2 degrees Celsius and boils near 58.8 degrees Celsius. A sufficiently cold sample becomes solid, and sufficient heating produces gas. The same element can therefore occupy all three familiar physical states without changing its chemical identity.

Bromine is a halogen, grouped with fluorine, chlorine, iodine, and other related elements. Elemental bromine commonly consists of Br₂ molecules, each containing two bromine atoms. Down the group, increasing molecular size and polarizability strengthen the intermolecular attractions that help determine melting and boiling behavior. The pattern gives fluorine and chlorine as gases, bromine as a liquid, and iodine as a solid at familiar indoor temperatures. This comparison concerns elemental substances, not all compounds containing those elements.

The distinction between bonds inside a molecule and forces between molecules is important. Boiling bromine mainly separates Br₂ molecules from one another; it does not require splitting every molecule into individual atoms. Likewise, melting changes their arrangement and mobility without redefining the element. A visible state change should not be confused with a chemical reaction. This is one reason phase behavior can be discussed separately from the reactions that bromine undergoes with other materials.

The discovery is associated with Antoine-Jérôme Balard and Carl Löwig in the nineteenth century, with 1826 commonly given as the discovery year. Its name derives from a Greek word associated with stench, reflecting its pungent odor. That historical naming detail is not an invitation to identify a sample by smelling it. Bromine is corrosive and hazardous, and its vapor can cause serious irritation and injury. Its appreciable volatility means an open container is dangerous even when the bulk substance remains liquid.

In nature, bromine is usually encountered as bromide ions in salts and brines rather than as pools of free elemental liquid. Industrial production separates and oxidizes bromide from suitable sources. The resulting element can be used to make bromine-containing chemicals for several applications. As with chlorine and chloride, chemical form changes properties substantially: a bromide ion in a salt is not equivalent to a molecule of elemental bromine. Risk and function must be assessed for the actual compound and exposure.

Mercury provides the obvious comparison because it is also liquid in a typical room, but mercury is a metal. Gallium and cesium melt at temperatures near warm-room conditions and complicate loose claims about “only two liquid elements.” A precise statement names the temperature range, pressure, and metallic classification. Bromine's status is not a mysterious exception to physical law; its intermolecular attractions place the liquid stability range across temperatures people happen to regard as comfortable indoors.

Bromine separates two classifications that are often confused: chemical character and physical state. A liquid is not automatically metallic, and a nonmetal is not automatically a gas or brittle solid. Temperature and pressure describe the conditions under which the state statement applies.