1,2,3,4,5-Pentafluorobenzene stands out as a remarkable organofluorine compound, shaped by the presence of five fluorine atoms attached to the benzene ring. The chemical formula, C6HF5, shows a straightforward structure—one hydrogen atom and five fluorine atoms circling a six-carbon ring. Each fluorine atom attaches to a separate carbon, leaving a single hydrogen to round out the molecule. Its molecular weight comes in at about 168.06 g/mol. Those numbers aren't just trivia; they tell us how this compound moves through lab processes or reacts in synthesis. With a CAS number of 602-94-8, it’s trackable in just about every major chemical database or regulatory list. The HS Code for customs documentation and international trade falls under 2903.39.9090, lining up alongside other organofluorine compounds.
On the shelf, 1,2,3,4,5-Pentafluorobenzene comes in more than one style. The pure compound typically appears as a colorless, clear liquid under standard conditions, but under controlled scenarios, it can solidify as flakes or crystalline solids, depending on temperature. Some suppliers offer this chemical as a powder or even as larger solid pearls for specialized industrial orders. Less often, it may ship as a solution in organic solvents, tailored for precise laboratory needs or manufacturing batches that require premixed compositions. Material purity matters here, because trace contaminants can disrupt sensitive pharmaceutical or electronics applications.
Structurally, this compound draws attention for the unique placement of fluorine atoms. These five substituents line up side-by-side on the benzene ring, changing both the physical shape of the molecule and its reactivity. The electron-withdrawing nature of fluorine arms the molecule with increased stability, especially against oxidation, and lowers its nucleophilicity, making it less likely to engage in demanding chemical reactions unless pushed by the right reagents. The molecule’s planarity allows it to stack efficiently with certain substrates, a behavior that surfaces in liquid crystal or display technologies.
Talking specs, 1,2,3,4,5-Pentafluorobenzene boils at about 84°C under normal atmospheric pressure. It melts around -17°C. Its density reads roughly 1.53 g/cm³ at 25°C, which is denser than many common solvents. The colorless appearance signals high purity. Vapor pressure runs around 27 mm Hg at 25°C—this volatility matters when planning storage or ventilation in a workspace. Solubility leans low in water but high in nonpolar organic solvents, supporting its use as a building block in organic synthesis. I’ve worked in laboratories where its distinct aromatic, almost sweet odor was a dead giveaway during distillation, signaling presence even without sophisticated analytic tools. Storage containers must seal tightly, not just for safety but to keep the compound from evaporating out over time.
1,2,3,4,5-Pentafluorobenzene gets its main run as a raw material or intermediate. In pharmaceuticals, researchers chase complex fluorinated drug candidates because fluorine tweaks the metabolic stability and bioactivity of molecules. The electronics industry values the compound’s unique dielectric properties for liquid crystal displays and semiconductor research. I’ve seen custom syntheses that start with pentafluorobenzene for the production of fluorinated polymers, where small changes in molecular arrangement yield significant performance jumps under real-world testing. It finds use in the agrochemical sector for similar reasons—pesticides and herbicides prepared from fluorinated aromatics often last longer while using smaller quantities because of improved activity profiles.
Fluorinated aromatic compounds deserve respect. 1,2,3,4,5-Pentafluorobenzene is harmful if inhaled or absorbed through skin, and labs must use proper fume hoods and gloves. Splash contact can cause irritation. Inhalation of vapor or mists has knocked down experienced chemists for the rest of a workday, so personal protective equipment is not optional. Spills ask for immediate attention—absorbent material, bagging, and careful disposal as hazardous waste. While the compound does not light up easily, high concentrations of vapor still pair with an open flame for trouble. Regulatory filings, including SDS (Safety Data Sheets) and strict inventory controls, keep everyone safe and compliant with both local and international laws. Fire suppression needs chemical agents, not water, because reactions between fluorinated aromatics and water under fire can kick up toxic fumes.
Managing solvent waste is one of the overlooked headaches with 1,2,3,4,5-pentafluorobenzene. Some labs have moved to micro-scale syntheses, where each reaction uses milligrams of material instead of grams or kilograms, slashing the risk and clean-up burden by an order of magnitude. Waste solvent collection and professional disposal services have grown into a basic business cost for chemical manufacturers. Installing solvent recovery systems—either on-site or through third-party vendors—can claw back reusable fluids and lower environmental impact.
What counts most is matching technical promise with practical safety. Fluorinated aromatics bring cutting-edge performance to high-stakes industries, but they demand commitment to workplace safety and environmental responsibility. Experience says that the best results come from multi-disciplinary teams—chemists, engineers, EH&S professionals—working together on clear protocols for handling and storage. People underestimate the value of routine; regular training, auditing storage conditions, and thorough documentation can make all the difference between a routine day and one marked by paperwork and health reports. For businesses and researchers looking to step up their game or move into new markets, understanding core materials like 1,2,3,4,5-pentafluorobenzene—straight down to their structure, hazards, and documentation—sets a foundation for success built on both innovation and trust.
