Formation of Lanthanide Oxides

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the ratio of oxygen atoms to another element in sesquioxides?

One to one

Two to three

Three to two (correct)

Four to five

Which lanthanide metals can form LnO2 when heated?

All lanthanide metals

Only La, Ce, and Tb

Ce, Pr, and Tb (correct)

Only Nd and Sm

What is the formula for the common sesquioxides?

LnO

Ln2O3 (correct)

Ln3O2

LnO2

How can the common sesquioxides be made?

By heating lanthanide metals in air or heating oxy-compounds such as nitrate or carbonate Signup and view all the answers

What is the name of the type of oxide compound formed by lanthanide metals?

Sesquioxide Signup and view all the answers

What is the temperature at which Nb3Ge has zero resistivity?

30 K Signup and view all the answers

What is the structural type of Ln2O3 with LnO6 units?

C-type Signup and view all the answers

How are divalent oxides of lanthanides prepared?

By reduction of Ln2O3 with elemental lanthanide Signup and view all the answers

What is the structural feature of A-type Ln2O3?

LnO7 capped-octahedra Signup and view all the answers

Which of the following lanthanides is not mentioned as having a divalent oxide?

Gd Signup and view all the answers

What is the primary factor that determines the coordination geometry of a metal?

The size and shape of the ligands Signup and view all the answers

What is a characteristic of the coordination chemistry of lanthanides Ln3+?

Forming complexes with high coordination numbers Signup and view all the answers

Why does no particular shape or coordination geometry dominate in metal-ligand complexes?

Due to the varying size and shape of the ligands Signup and view all the answers

What type of compounds are LnX3?

Inorganic compounds Signup and view all the answers

What is the primary function of 'self-cleaning' ovens?

To prevent the buildup of tarry deposits Signup and view all the answers

What is the oxidation state of the lanthanides in their coordination chemistry?

Ln3+ Signup and view all the answers

What is the reaction required to prepare anhydrous halides LnX3?

Heating the metal and the halogen Signup and view all the answers

Which of the following is a consequence of the varying size and shape of ligands?

No particular shape or coordination geometry being preferred Signup and view all the answers

What is the reason for the high coordination numbers of lanthanide complexes?

Large ionic radii of lanthanides Signup and view all the answers

What is the characteristic of ligands that influences the coordination geometry of a metal?

Their steric demands Signup and view all the answers

What is the relationship between the size and shape of ligands and the coordination geometry of a metal?

The size and shape of the ligands determine the coordination geometry Signup and view all the answers

What type of ligands are commonly found in lanthanide complexes?

A variety of ligands, including monodentate and polydentate Signup and view all the answers

What is the significance of the high coordination numbers of lanthanide complexes?

They can accommodate a variety of ligands Signup and view all the answers

What is the purpose of heating the metal and the halogen in the preparation of anhydrous halides LnX3?

To initiate the reaction between the metal and the halogen Signup and view all the answers

What is the common characteristic of 'self-cleaning' ovens and the preparation of anhydrous halides LnX3?

Both involve heating Signup and view all the answers

Study Notes

Sesquioxides and Lanthanides

Sesquioxides have a ratio of 3 oxygen atoms to 2 of another element, typically forming the general formula of ABO₃.
Lanthanide metals that can form LnO₂ when heated include Ce, Pr, and Nd.
Common sesquioxides include compounds such as La₂O₃, Nd₂O₃, and Sm₂O₃, characterized by having two metal ions and three oxygen atoms.
Common sesquioxides can be prepared through solid-state reactions or by oxidation of lanthanide metals.
Lanthanide metals form a specific type of oxide known as lanthanide oxides or rare earth oxides.

Properties and Structures

Nb₃Ge exhibits zero resistivity at a critical temperature known as the superconducting transition temperature, which is approximately 7.3 K.
The structural type of Ln₂O₃ featuring LnO₆ units is typically hexagonal or cubic.
Divalent oxides of lanthanides are generally prepared through the reduction of their corresponding trivalent oxides using alkaline earth metals or other reducing agents.
A-type Ln₂O₃ displays a characteristic structural feature of a double-defect fluorite structure.
Gadolinium is often noted as an exception among lanthanides lacking a divalent oxide.

Coordination Chemistry

The primary factor determining metal coordination geometry is the size and charge of the metal ion.
A notable characteristic of lanthanide coordination chemistry is the preference for high coordination numbers, often ranging from 6 to 12.
The absence of a dominant particular shape in metal-ligand complexes arises from the variable sizes and shapes of ligands in coordination environments.

LnX₃ and Halides Preparation

Compounds of the form LnX₃ are trivalent halides of lanthanide elements, often used in various chemical applications.
Self-cleaning ovens function primarily through high-temperature pyrolysis of organic residues into ash and gases, a process resembling the preparation of anhydrous halides.
In their coordination chemistry, lanthanides primarily exhibit a +3 oxidation state.
The preparation of anhydrous halides LnX₃ involves the reaction between lanthanide metals and halogens under controlled heating to prevent moisture uptake and ensure purity.

Ligands and Coordination Geometry

Ligands influencing coordination geometries often exhibit specific steric and electronic characteristics impacting metal interactions in complexes.
High coordination numbers in lanthanide complexes signify the ability of these metals to stabilize larger coordination environments, impacting their reactivity and properties.
A relationship exists where the size and shape of ligands significantly influence the resulting coordination geometry of a metal, with larger ligands generally leading to more complex geometric arrangements.
Lanthanide complexes often contain chelating ligands or organic molecules that promote favorable coordination geometries to accommodate the large trivalent cations.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the preparation of sesquioxides, Ln2O3, and oxides LnO2, from lanthanide metals and oxy-compounds. Understand the formation of these compounds through heating processes.