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Sulfuric acid has a backstory as gritty as the smokestacks and chemical plants it finds itself in today. Medieval alchemists tried to make gold, but out of those wild experiments grew a growing pile of knowledge about strong acids. Ancient Arab chemists produced early forms by heating minerals containing sulfates, long before anyone could reliably label a flask. Later, the lead chamber process changed the game for industry in the 18th century, bringing a consistent supply—though impurities became a dirty secret. Once chemists figured out the contact process with catalysts, factories churned out acid pure enough for fertilizers, explosives, and batteries. Every new method told a story about the world’s hunger for steel, mining, and synthetic dyes. Sulfuric acid tracked the progress of whole economies, from England’s textile mills to mega-plants in China and the US. History books rarely mention it, but work crews mixing acids and handling hot vats laid the chemical groundwork for so much of the modern world.
This isn’t the kind of acid you keep in the back of the fridge or under the kitchen sink. Sulfuric acid means business. Produced on a scale of millions of tons a year, it usually shows up as an oily, clear or slightly yellow liquid. In labs, 98% concentrated sulfuric acid gets shipped in heavy-duty drums or tanker trucks, sometimes tagged as “oil of vitriol”—a name that sounds medieval for a good reason. In factories, bulk buyers want it clean, with little water, and they watch supply chains closely because it serves as a workhorse for factories. The acid finds its way into processes making phosphate fertilizers, cleaning up petroleum, producing dyes and paints, and even bleaching paper to a blinding white. What sets it apart isn’t just its chemical punch but the way it’s woven into global trade, agriculture, and big industry.
Stare at a canister of sulfuric acid and you won’t get dazzled by color or sparkle. It’s a viscous, mostly colorless liquid, but pour it near water and feel the heat: it grabs water with ferocity, releasing energy, and can boil or spit in seconds. This strong acid grabs hydrogen ions fast—its strength relentless, with a pH nearly scraping zero when labeled “concentrated.” Under standard temperature and pressure, its boiling point towers at roughly 337°C, proof of the heavy, tightly packed molecules inside. While most think of acids corroding surfaces, sulfuric acid prefers to strip water from whatever it meets—turning sugar into a black, charred mass, or ruining fabric in a heartbeat. With its density higher than water and a tendency to soak any moisture in the air, storing it demands respect.
Factories stamp labels hard when trading sulfuric acid. Bottles or tanks bear essential numbers: the acid concentration—measured by mass percent or molarity—and the density. Reliable producers stick to clear specifications: technical grade, reagent grade, or battery acid, depending on iron, arsenic, or other impurities. Regulations require marking clear hazard statements, not just for shipment but for safety at every stage. In my work, purchasing managers always check batch numbers and test reports so no one gets caught by an off-spec batch—especially when dealing with industrial scale where a barrel too concentrated, or not concentrated enough, ruins production lines or, worse, safety barriers. Quality control labs run tests with precision, watching for contamination or unexpected compounds.
Manufacturers bring together chemistry and engineering muscle to make sulfuric acid at scale. The so-called “contact process” starts with sulfur burning in air, forming sulfur dioxide—this feeds into tall towers packed with catalyst, where the gas meets more oxygen to form sulfur trioxide. Mix these oxides carefully with water, and you’ve got sulfuric acid, usually in a concentrated form. Factories use advanced materials to handle the fierce heat and the acid’s appetite for water. A slip-up means metal leaks, corrosion, or nasty emissions. Older plants sometimes use the “lead chamber process” for lower purity needs, but contact process dominates global production. All those practical learnings—heat controls, gas flows, scrubbing out impurities—came from decades of engineers learning the hard way.
Sulfuric acid doesn’t just cut; it builds. Its double-hydrogen punch lets it work as a dehydrating agent—key for drying gases or breaking down biomass. It serves as a catalyst, nudging hydrocarbons around in refineries, churning out high-octane fuels. Mix it with metals, and you get sulfates, bubbling up hydrogen gas as a side effect. In fertilizer production, sulfuric acid unlocks phosphorus from rock and helps make ammonium sulfate. Sometimes, chemists "cut" the acid with water to the right strength for batteries or fertilizer plants. Its reactivity keeps chemists on their toes in labs, where it helps strip away water, break complex molecules, or drop out new compounds from solution. Any process tweaking the acid—whether for pigment-making, sulfate salts, or explosives—relies on knowing exactly how it’ll behave with other chemicals in the mix.
Pick up a chemical catalog and sulfuric acid might wear several names. The older generations call it “oil of vitriol.” Trade paperwork might read “sulphuric acid” in European markets. In battery shops, “battery acid” speaks plainly. Scientists mark it by chemical formula—H₂SO₄—or by grade: technical, reagent, or battery. Some papers reference “vitriol” from older texts, tracing a lineage back to ancient glass vials and hand-drawn diagrams. Whether in modern warehouses or in historical notes, the acid’s many names tell a story about where and how it’s been used. People across the world have learned to handle and respect the material through an evolving vocabulary passed down from generations of chemists, laborers, and engineers.
Sulfuric acid’s danger isn’t a secret. Put a drop on skin and you’ll feel the sting. It burns through organic material, metal, and protective gear too weak for the job. In my early years working with acids, wearing splash goggles, face shields, and rubber gloves became a ritual. Spill procedures matter as much as fire drills—dry sand beats water for neutralizing spills, and first-aid stations stand ready with copious amounts of water to rinse accidental contact. Industrial settings follow international regulations—the Globally Harmonized System for labels, OSHA requirements for handling, and permits for shipment. Storage tanks sit under strict temperature and material controls, as sulfuric acid reacts with many common metals, risking leaks or ruptures. Staff earn their stripes learning safety data sheets by heart, because chemistry doesn’t forgive carelessness.
Walk through any chemical plant, mining operation, or battery factory and sulfuric acid finds its way in. One major use sits in making phosphate fertilizers to feed global agriculture—a process that turns raw phosphate rock into soluble forms crops can use. Refineries count on sulfuric acid to remove impurities in crude oil, especially for making cleaner gasoline and diesel. In metal ore refining, acid leaches valuable metals from rock or waste. Lead-acid batteries—powering cars, backup systems, and forklifts—all use diluted sulfuric acid. Textile workers use it to treat fibers, dye houses use it for pigments, and paper mills depend on it to process wood pulp. The reach of this acid shows up from farm fields to big city power grids.
Chemists and engineers tackle sulfuric acid problems with a mix of old-school lab work and new technology. Researchers push for greener ways to reclaim spent acid from waste streams—important for reducing environmental impact, especially in copper smelting and battery production. Nanotechnology opens doors for tiny sensors that can detect leaks early, preventing disasters in factories. Electrochemical techniques look to use less energy or cut out byproducts. Teams in universities and commercial labs chase catalysts that can handle higher temperatures, ramping up output while using less platinum or vanadium. Ongoing research documents how different acid strengths change reaction yields or improve plant safety, giving industry a roadmap for tighter controls and greener practices.
Medical teams and toxicologists study sulfuric acid not only for its direct dangers but for the longer-term risks of chronic exposure. Inhaled fumes corrode the respiratory system, while concentrated acid splashes mean chemical burns—both send people into emergency rooms. Workplace studies show increased risk in accidents when safety lapses or improper protective gear get involved. Researchers track acid mist and droplets in air, linking exposure to elevated rates of respiratory issues in nearby communities. Statistical analysis of industrial accident data helps regulators update exposure limits and improve factory ventilation standards. Scientists conduct experiments on animal models to guide antidotes or emergency protocols. Every new study ratchets up industry awareness: safety isn’t just a rule, it’s protection against chemical tragedy.
People sometimes overlook that global challenges—like food production, clean energy, or sustainable manufacturing—all pull for more sulfuric acid, but with cleaner processes. Green chemistry circles talk about recycling used acid and cutting greenhouse emissions from burning sulfur. Battery research focuses on safer forms for storage and recycling, lowering risks in cars and grid-scale energy systems. Digital systems using sensors and real-time tracking help minimize accidental releases and boost efficiency. Major refineries and mining projects continue to use massive quantities, but the next wave of innovation promises smarter plants, where AI-controlled systems optimize dose, purity, and safety. Higher environmental standards press factories to reduce waste and recycle sulfur-containing byproducts, turning a centuries-old chemical into a cornerstone for tomorrow’s industries.
Growing up on a farm, every summer I watched my parents puzzle over their crops. Some years, our corn looked strong, sometimes it barely grew. Later on, I learned that so much of what goes on underground comes down to what we put back into the earth. This is where sulfuric acid plays a giant role. Most of the fertilizer used today starts with sulfuric acid, especially phosphatic fertilizers. Manufacturers use this acid to turn raw phosphate rock into plant food. If you’ve ever heard a farmer talk about crop yield or food security, chances are, sulfuric acid had a role back at the beginning.
Living in a city, it’s easy to forget that steel comes from somewhere. Before that metal ends up as a bridge or a skyscraper, it has to be cleaned, shaped, and protected. The acid cleaning bath removes rust and scale from steel and iron before they’re made into something useful. At the steel plant near my town, the smell sometimes spread for miles. That was sulfuric acid at work, cleaning and prepping metal so it could last longer and perform better.
Everyone has a story about a dead car battery. What most people never realize is that the reliable crank under the hood depends on sulfuric acid. Battery acid is not some abstract invention—it’s essentially diluted sulfuric acid. Every time you start a car, power emergency lighting, or use some types of backup systems, sulfuric acid is making that spark possible. Even now, lead-acid batteries hold a massive share of the market for cars, trucks, and industrial vehicles.
During college, I toured a factory that made nylon. The process fascinated me. Sulfuric acid, one of the first chemicals used in production, helps turn raw oil and gas into new fibers. Yarn for clothing, tire cord for trucks, everyday plastics—sulfuric acid steps in early to enable these transformations. Chemists rely on it to make products stronger and more versatile.
In cities, drinking water comes from underground reserves, rivers, and lakes. Along the way, it picks up stuff nobody wants to swallow. Water treatment plants often use sulfuric acid to control pH and make purification more efficient. By keeping water at the right acidity, other chemicals can do their jobs better, removing metals and germs before water reaches your glass or shower.
Sulfuric acid doesn’t get much attention compared to glitzier topics, but it's woven into the fabric of modern life. The Environmental Protection Agency tracks its production as a key sign of industrial growth. Its powerful nature means people must handle it with respect, and spills or mismanagement can have real consequences for water and land. Improved training, strict handling standards, and ongoing monitoring reduce the risks that come with widespread use. Investments in safer storage and better spill prevention will keep workers safe and protect local communities.
From growing crops to building cities and cleaning water, sulfuric acid’s reach is huge. The demand isn’t going away soon. As renewable batteries, new construction materials, and clean water projects pop up around the world, this unassuming chemical will still hold a place in the toolkit. It’s worth paying attention to where and how it’s used—not just for industry, but for the health of our world.
Most folks who have handled strong chemicals can tell you that sulfuric acid will eat through your jeans and scorch your shoes in seconds. Its reputation for causing serious burns and smoke isn’t exaggerated. Even in places decked out with warning labels, people take shortcuts. I’ve seen what happens when someone tops off a car battery without gloves or pours it straight from the wrong bottle. Lasting scars, hospital trips, hours of breathing issues—these aren’t rare outcomes.
Looking at any safety data sheet, the message comes across loud and clear: cover up. At minimum, someone should wear splash-proof goggles, a well-fitted lab coat, chemical-resistant gloves, long pants, and closed shoes—preferably rubber. Face shields aren’t just for show, either. Acid finds every little gap: a drop around the goggles or a trickle at the wrist, and you’ll feel it right away.
According to the National Institute for Occupational Safety and Health, sulfuric acid ranks among the top causes of skin and eye injuries in industrial settings. You can’t rely on regular latex gloves; they dissolve too quickly. Nitrile or neoprene holds up longer, but even those need swapping out before any signs of wear.
Few things cause more confusion than a workbench full of mystery bottles. I’ve seen plain water flasks kept right next to acid containers. Poor labeling leads to mistakes. Every container should have a label stating exactly what’s inside, with clear hazard warnings. Big, bold writing beats fancy color-coded caps. If you’re pouring acid into a secondary container, make sure it’s glass or a special plastic designed for corrosives. Regular plastic breaks down over time.
Keep sulfuric acid away from organics, water, or anything that could trigger a reaction. That rule comes from simple experience. I once saw an entire storage room get evacuated because someone decided to store sulfuric acid next to bleach. The fumes nearly sent half the crew to the ER.
Mixing acid with water catches a lot of people off-guard. "Always add acid to water, never the other way around." That’s not just folklore; it prevents violent splashing. You’ll get an eruption every time if you reverse the order. Don’t rush—use a slow, steady pour and glass stirring rods. Keeping emergency rinsing stations and eyewash showers within reach isn’t just a regulation—if something goes wrong, every second counts.
Mechanical ventilation means more than cracked windows. Sulfuric acid puts off fumes strong enough to burn your lungs. Labs and workshops need real fume hoods or stand-alone local exhaust fans. Without them, even short exposure stings your airways and eyes. Occupational Safety and Health Administration standards call for ventilation in any room where acids get used or stored.
People forget. Safety videos fade from memory after a few weeks. In my own training sessions, running hands-on drills always sticks better than long lectures. Practicing with spill kits and proper clean-up routines turns theory into something memorable. Sometimes, seeing a dummy test with a splash on a pair of pants is worth ten warnings on a printed sheet.
No one plans to get hurt, but sulfuric acid won’t forgive a lazy move. Whether you’re in a school lab, a garage, or a busy plant, it only takes one shortcut to regret it for years.
Sulfuric acid has shaped industries, schools, and even high school science classrooms, but it’s stubborn in how it interacts with pretty much everything. If you leave a drop on your skin, it burns. Drip it on metal, and you see corrosion almost instantly. Anyone who has ever cracked open a car battery or pulled a chemistry prank (never a good idea) knows that storage isn’t something to improvise. People’s safety relies on getting the basics right.
Many folks treat containers as afterthoughts, but acids don’t care about your good intentions. My old lab director swore by high-density polyethylene (HDPE) drums—he learned the hard way after a glass carboy incident left a permanent patch etched into the tile. Steel can get eaten through. Even stainless steel struggles if fuming concentrates or mixed with traces of chlorides.
Plastic resists sulfuric acid’s aggression. Polyethylene, especially HDPE, sticks around. Anybody who has tried to cut corners with other plastics—PVC, for example—soon faces splitting or crumbling. For larger sites, polyethylene-lined tanks work well. Fiberglass reinforced plastic sometimes comes up, but cost and handling can be a pain.
The environmental mess after a spill haunts local communities and usually winds up on the news. Drains near sulfuric acid tanks invite trouble, and simple cracks in the floor help acid find its way to groundwater. Secondary containment, using acid-proof bund walls or double-walled tanks, buys crucial time to catch leaks before they leave the building. At my last workplace, even with regular inspections, we found tiny seeps along aging joints—always at the most inconvenient times.
If you’ve worked around warehouses, you know trust in the floor is never enough. Concrete turns to mush after a little acid exposure. Lining storage areas with chemical-resistant coatings—special epoxies made for acids—makes sense for anyone who values their flooring and water supply.
Anybody who has dealt with acid fume knows they spread quickly. Just a warm day helps evaporation, and vapor finds its way toward people and electrical gear. Chemical burns inside a warehouse or lab aren’t dramatic Hollywood explosions—they just mean someone trips, drops a rag, or breathes wrong at the wrong second. Good ventilation matters, pulling air away from the tanks, and ductwork keeps sulfur dioxide out of everyone’s lungs.
I still remember a factory shift in August, when a heatwave led to vapor clouds pooling around roof beams. Keeping temperature steady, away from both blazing heat and freezing conditions, means less pressure inside containers and fewer headaches.
All the engineered barriers don’t mean anything if people wing it around acids. My first role involved watching a new hire try to “quickly” decant acid between jugs with no gloves—he landed in the emergency eyewash three times that month. Training beats overconfidence, so refresher sessions and drills matter. Emergency gear like neutralizing powders, spill kits, and working showers turns chaos into a manageable cleanup. Proper signage and documentation help new faces understand the risks.
Anyone who stores hazardous chemicals has paperwork, inspections, and legal hoops. Proper labeling and up-to-date storage logs cut confusion during emergencies and routine checks. The aim here isn’t to bog folks down with bureaucracy, but to keep lives safe and neighborhoods unscarred. Sulfuric acid always finds mistakes, and prevention always works out cheaper than cleaning up.
Sulfuric acid ranks as one of the most widely used industrial chemicals. The question of concentration always crops up because it shapes how the acid works in every application. For most folks in chemical manufacturing or even in a school lab, the phrase “concentrated sulfuric acid” usually points to a product around 98% pure by weight, mixed with a little bit of water.
Labs and factories have stories about sulfuric acid mishaps—spills, burnt sleeves, odd fumes lingering in the air. The concentration tells you a lot about what’s possible, risky, or even forbidden without careful handling. I once saw someone in a workshop mistakenly reach for a bottle labeled “battery acid” (about 30-35%). Their process called for the concentrated stuff, and they quickly learned that weak acid just couldn’t deliver the same punch. The difference showed up in sluggish reactions. Industries can’t afford that kind of mix-up.
Experts point out that industrial sulfuric acid often hovers close to 98%. Go past that mark, even by a fraction, and the acid starts sucking up water from the air fast. That’s more than a technical point—it changes how you store and move the acid. Sulfuric acid at 98% can sit in steel tanks with less fuss. Drop down to 70% or 50%, and the acid needs extra care or different tank linings, because it’s more likely to corrode metal or even plastic over time.
A lot of school chemistry sets include only weak sulfuric acid. That’s no accident. Strong, nearly pure acid pulls so much heat out of a water mix that careless handling can cause explosions of steam. I learned that lesson during a high school demonstration gone sideways—a cloud of steam, a ruined countertop, and a lasting respect for those numbers on the label.
Regulatory agencies such as OSHA and the EPA require clear documentation that spells out concentration because public health rides on those numbers. Chemical supply companies have gotten much sharper at labeling. Years ago, some sources only labeled containers as “sulfuric acid” and left customers guessing. That doesn’t cut it now. MSDS sheets spell out the concentration and describe the risks, from burns to toxic fumes if the acid touches strong chemicals like nitric acid or organic matter.
Knowing the exact concentration helps buyers check if they can use the acid for applications like fertilizer production, metal pickling, or pH control in water treatment. Out in the field caring for machinery, a misstep—a half-strength acid swapped for full-strength—can trash a piece of equipment or pollute a water supply. There’s a reason technicians check and re-check with titration kits or refractometers before pouring acid into a system.
Cleaner labeling and strict packaging help cut down on mistakes, but talking openly about these numbers matters just as much. Training matters, too. Rushing a delivery or skipping a label check often leads to dangerous, expensive errors. Plants now hand out cheat sheets detailing acid concentration for each task. Those small steps add up when you’re wrestling with something as powerful and unpredictable as sulfuric acid.
Sulfuric acid’s reputation comes just as much from its dangers as its utility. Every percent in the bottle tells a story—about reactivity, about safety, about doing the job right the first time. Relying on real world experience, not just labels or paperwork, gives everyone—from chemists to plant operators—the edge to use it wisely.
Sulfuric acid doesn’t just eat away at metal. It can chew through skin, burn plants, ruin plumbing, and trash water quality in a heartbeat. Anyone who handles it in a school lab, a car battery shop, or a home project probably feels the worry buzzing in the back of their head, and for good reason. From experience in my own garage, I can say: a splash on jeans leaves a hole. A spill in a sink means expensive pipes and a call to a plumber. Down the drain isn’t an option. Out in the yard means a big brown dead patch for ages, plus the real risk of harming kids, pets, and local wildlife.
Household waste rules slam the door shut on pouring harsh acids in the trash. Landfills aren’t built to deal with chemicals that burn or eat through steel drums. Regulators consider sulfuric acid a corrosive hazardous waste, and fines for breaking these rules cut deep into a budget. Local environmental agencies, and the Environmental Protection Agency, classify it as hazardous under federal law. One mishap leads to ground pollution, fish kills, or even explosions if the acid meets the wrong materials.
Stores that sell batteries or pool chemicals typically don’t take acid back, though that’s often the first hope. Friends of mine have tried to pawn sulfuric acid off on these stores and hit a brick wall. The “neutralize it with baking soda and wash it away” myth floats around online. Truth is, pouring sodium bicarbonate on concentrated acid unleashes a nasty heat burst and dangerous splashing. Even diluted, leftover salts and water can leave nasty stuff behind, and local wastewater plants don’t want surprise acid in their systems.
Getting in touch with the local hazardous waste collection center remains the most reliable fix. Nearly every county provides this service a few times a year. Some will set appointments for old paint and solvents, along with household acids. My own town has a spring “chem drive,” and I put sulfuric acid in a sealed, original container in my car trunk, separated from everything else, and stood in line for maybe twenty minutes. Trained workers wore goggles and heavy gloves. They grabbed the bottles, asked a few questions about the source, and issued a slip as a record. Not glamorous, far from fast, but extremely effective.
Schools, labs, and businesses build disposal into their safety plans. They call in licensed hazardous waste haulers, who bring drums and proper chemical neutralizers. Big-quantity neutralization happens under professional oversight. That way, acid never ends up mixing with city water or landfill runoff.
Too many communities hide their hazardous waste programs behind hard-to-search websites or lock them in red tape. Public service reminders should make a clear, bold point—never dump sulfuric acid into drains, toilets, ditches, or garbage bins. Outreach and clear drop-off events matter. Retailers could do more to point these options out at the point of sale. Safe acid disposal should feel less like jumping through hoops and more like another responsible, everyday task.
A big lesson: mishandling sulfuric acid doesn’t just hurt pipes or plants—it sticks around for years. Getting the word out, and making responsible disposal obvious and accessible, protects everyone’s health, budget, and neighborhood.
| Names | |
| Preferred IUPAC name | Dihydroxidooxidosulfur |
| Other names |
Oil of vitriol Hydrogen sulfate Battery acid Dihydrogen sulfate Sulphuric acid |
| Pronunciation | /ˌsʌlˈfjʊərɪk ˈæsɪd/ |
| Identifiers | |
| CAS Number | 7664-93-9 |
| Beilstein Reference | 3597153 |
| ChEBI | CHEBI:26836 |
| ChEMBL | CHEMBL1233611 |
| ChemSpider | 1073 |
| DrugBank | DB09312 |
| ECHA InfoCard | 03-2119454166-44-0000 |
| EC Number | 231-639-5 |
| Gmelin Reference | Gmelin Reference: "199 |
| KEGG | C00059 |
| MeSH | D013403 |
| PubChem CID | 1118 |
| RTECS number | WS5600000 |
| UNII | F07277R725 |
| UN number | UN1830 |
| Properties | |
| Chemical formula | H2SO4 |
| Molar mass | 98.08 g/mol |
| Appearance | Clear, colorless to slightly yellow, oily liquid |
| Odor | Odorless |
| Density | 1.84 g/cm³ |
| Solubility in water | Miscible |
| log P | -2.07 |
| Vapor pressure | 0.001 mmHg (20°C) |
| Acidity (pKa) | -3.0 |
| Basicity (pKb) | -3.0 |
| Magnetic susceptibility (χ) | −40.6×10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.429 |
| Viscosity | 26.7 cP (at 20°C) |
| Dipole moment | 2.99 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 156.9 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -814 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -814 kJ·mol⁻¹ |
| Pharmacology | |
| ATC code | V03AB14 |
| Hazards | |
| Main hazards | Corrosive, causes severe skin burns and eye damage, may cause respiratory irritation |
| GHS labelling | **"GHS02, GHS05, GHS07, GHS08"** |
| Pictograms | GHS03,GHS05 |
| Signal word | Danger |
| Hazard statements | H290, H314, H318 |
| Precautionary statements | P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501 |
| NFPA 704 (fire diamond) | 3-0-2-W |
| Autoignition temperature | 450°C (842°F) |
| Lethal dose or concentration | LD50 oral rat 2140 mg/kg |
| LD50 (median dose) | LD50 (median dose) of Sulfuric Acid: "2140 mg/kg (rat, oral) |
| NIOSH | WS5600000 |
| PEL (Permissible) | PEL = 1 mg/m³ |
| REL (Recommended) | Level 1 |
| IDLH (Immediate danger) | 15 mg/m³ |
| Related compounds | |
| Related compounds |
Disulfuric acid Chlorosulfuric acid Peroxydisulfuric acid Sulfurous acid Oleum Sulfur trioxide Thiosulfuric acid Sulfur dichloride |
