chemistry

Gadolinium oxysulfide

Gadolinium oxysulfide 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 Gadolinium oxysulfide rather than just read about it. In short: Gadolinium oxysulfide (Gd2O2S), also called gadolinium sulfoxylate, GOS or Gadox, is an inorganic compound, a mixed oxide-sulfide of gadolinium. Structure Gadolinium oxysulfide has a trigonal crystal structure (space group 164).

Key takeaways

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

Reference excerpt

Gadolinium oxysulfide (Gd2O2S), also called gadolinium sulfoxylate, GOS or Gadox, is an inorganic compound, a mixed oxide-sulfide of gadolinium.

Structure Gadolinium oxysulfide has a trigonal crystal structure (space group 164). Each gadolinium ion is coordinated by four oxygen atoms and three sulfur atoms in a non-inversion symmetric arrangement. The Gd2O2S structure is a sulfur layer with double layers of gadolinium and oxygen in between.

Uses

Ceramic scintillators The main use of gadolinium oxysulfide is in ceramic scintillators. Scintillators are used in radiation detectors for medical diagnostics. The scintillator is the primary radiation sensor that emits light when struck by high energy photons. Gd2O2S based ceramics exhibit final densities of 99.7% to 99.99% of the theoretical density (7.32 g/cm3) and an average grain size ranging from 5 micrometers to 50 micrometers in dependence with the fabrication procedure. Two powder preparation routes have been successful for synthesizing Gd2O2S: Pr, Ce, F powder complexes for the ceramic scintillators. These preparations routes are called the halide flux method and the sulfite precipitation method. The scintillation properties of Gd2O2S: Pr, Ce, F complexes demonstrate that this scintillator is promising for imaging applications. There are two main disadvantages to this scintillator; one being the hexagonal crystal structure, which emits only optical translucency and low external light collection at the photodiode. The other disadvantage is the high X-ray damage to the sample. Terbium-activated gadolinium oxysulfide is frequently used as a scintillator for x-ray imaging. It emits wavelengths between 382-622 nm, though the primary emission peak is at 545 nm. It is also used as a green phosphor in projection CRTs, though its drawback is marked lowering of efficiency at higher temperatures. Variants include, for example, using praseodymium instead of terbium (CAS registry number 68609-42-7, EINECS number 271-826-9), or using a mixture of dysprosium and terbium for doping (CAS number 68609-40-5, EINECS number 271-824-8).

Luminescent host material Gadolinium oxysulfide is a promising luminescent host material, because of its high density (7.32 g/cm3) and high effective atomic number of Gd. These characteristics lead to a high interaction probability for X-ray radiation. Several synthesis routes have been developed for processing Gd2O2S phosphors, including: solid state reaction method, reduction method, combustion synthesis method, emulsion liquid membrane method, and gas sulfuration method. The solid state reaction method and reduction methods are most commonly used because of their high reliability, low cost, and high luminescent properties. (Gd0.99, Pr0.01)2O2S sub-microphosphors synthesized by homogeneous precipitation method are very promising for a new green emitting material to be applied to the high resolution digital X-ray imaging field Gadolinium oxysulfide powder phosphors are intensively used for conversion of X-rays to visible light in medical X-ray imaging. Gd2O2S: Pr based solid state X-ray detectors have been successfully reintroduced to X-ray sampling in medical computed tomography (imaging by sections or sectioning, through the use of any kind of penetrating wave).

Safety Inhalation may result in lung injuries. Exposure to gadolinium compounds may cause lung and/or liver damage. Contact with the skin may cause rash, redness or dermatitis. When Gadolinium oxysulfide comes in contact with mineral acids, hydrogen sulfide can be produced.

References

Worked examples

Example 1 — a first encounter with Gadolinium oxysulfide

Start with the simplest possible case. Write down what Gadolinium oxysulfide 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 Gadolinium oxysulfide 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 Gadolinium oxysulfide 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 Gadolinium oxysulfide

In research: Gadolinium oxysulfide 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 Gadolinium oxysulfide 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: Gadolinium oxysulfide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gadolinium compounds, Oxysulfides, Phosphors and scintillators, so understanding it makes those chapters shorter.
In everyday life: Look for Gadolinium oxysulfide 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 Gadolinium oxysulfide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gadolinium oxysulfide 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 Gadolinium oxysulfide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gadolinium oxysulfide in simple terms?

Gadolinium oxysulfide (Gd2O2S), also called gadolinium sulfoxylate, GOS or Gadox, is an inorganic compound, a mixed oxide-sulfide of gadolinium. Structure Gadolinium oxysulfide has a trigonal crystal structure (space group 164).

Why does Gadolinium oxysulfide 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 Gadolinium oxysulfide?

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 Gadolinium oxysulfide.