chemistry

Lead(II) chromate

Lead(II) chromate is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lead(II) chromate rather than just read about it. In short: Lead(II) chromate is an inorganic compound with the chemical formula PbCrO4. It is a bright yellow salt that is very poorly soluble in water.

Key takeaways

Lead(II) chromate belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lead(II) chromate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lead(II) chromate from memory before moving on to harder problems.

Reference excerpt

Lead(II) chromate is an inorganic compound with the chemical formula PbCrO4. It is a bright yellow salt that is very poorly soluble in water. It occurs also as the mineral crocoite. It is used as a pigment (chrome yellow).

Structure

Two polymorphs of lead chromate are known, orthorhombic and the more stable monoclinic form. Monoclinic lead chromate is used in paints under the name chrome yellow, and many other names. Lead chromate adopts the monazite structure, meaning that the connectivity of the atoms is very similar to other compounds of the type MM'O4. Pb(II) has a distorted coordination sphere being surrounded by eight oxides with Pb-O distances ranging from 2.53 to 2.80 Å. The chromate anion is tetrahedral, as usual. Unstable polymorphs of lead chromate are the greenish yellow orthorhombic form and a red-orange tetragonal form.

Preparation Lead(II) chromate can be produced by treating sodium chromate with lead salts such as lead(II) nitrate or by combining lead(II) oxide with chromic acid. Related lead sulfochromate pigments are produced by the replacement of some chromate by sulfate, resulting in a mixed lead-chromate-sulfate compositions Pb(CrO4)1−x(SO4)x. This replacement is possible because sulfate and chromate are isostructural. Since sulfate is colorless, sulfochromates with high values of x are less intensely colored than lead chromate. In some cases, chromate is replaced by molybdate.

Applications

Approximately 37,000 tons were produced in 1996. The main applications are as a pigment in paints, under the name chrome yellow.

Reactions Heating in hydroxide solution produces chrome orange, a yellowish red or orange powder made by PbO and CrO3. Also, in hydroxide solution lead chromate slowly dissolves forming plumbite complex.

PbCrO4 + 4 OH− → [Pb(OH)4]2− + CrO2−4

Safety hazards Despite containing both lead and hexavalent chromium, lead chromate is not acutely lethal because of its very low solubility. The LD50 for rats is only 5,000 mg/kg. Lead chromate must be treated with great care in its manufacture, the main concerns being dust of the chromate precursor. Lead chromate is highly regulated in advanced countries. As one of the greatest threats comes from inhalation of particles, much effort has been devoted to production of low-dust forms of the pigment. In the 1800s, the product was used to impart a bright yellow color to some types of candy. It is used (illegally) to enhance the color of certain spices, particularly turmeric, particularly in Bangladesh. Unlike other lead-based paint pigments, lead chromate is still widely used, especially in road marking paint. In 2023 and 2024, consumption of adulterated cinnamon led to at least 136 cases of lead toxicity in children in the United States as reported by the US Centers for Disease Control and Prevention. The affected products were recalled. The US Food and Drug Administration determined that the ratio of lead to chromium in the cinnamon indicated that lead chromate had been added to the cinnamon.

Illustrations

Worked examples

Example 1 — a first encounter with Lead(II) chromate

Start with the simplest possible case. Write down what Lead(II) chromate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lead(II) chromate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lead(II) chromate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lead(II) chromate

In research: Lead(II) chromate appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lead(II) chromate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lead(II) chromate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chromates, Environmental impact of paint, Lead(II) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Lead(II) chromate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lead(II) chromate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lead(II) chromate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lead(II) chromate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lead(II) chromate in simple terms?

Lead(II) chromate is an inorganic compound with the chemical formula PbCrO4. It is a bright yellow salt that is very poorly soluble in water.

Why does Lead(II) chromate matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lead(II) chromate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lead(II) chromate.