Hydrogen; species; continues; table

Tetrasulfur tetranitride, S₄N₄, is a main group compound that __________ to intrigue chemists. These __________ feature elements from groups 1, 2 and 13-18 (excluding __________) of the periodic _________.

Exercise 2. Compose a story on one of the topics (up to 40 words):

“History of appearing compounds”

“Modern coordination compounds”

“The stereochemistry of coordination complexes”

Lesson 4

Read the text: Different types of compounds. Part II.

конецформыначалоформыTransition metal compounds

Copper phthalocyanine is a transition metal compound related to haem. Compounds containing metals from group 4 to 11 are considered transition metal compounds. Compounds with a metal from group 3 or 12 are sometimes also incorporated into this group, but also often classified as main group compounds.

Transition metal compounds show a rich coordination chemistry, varying from tetrahedral for titanium (e.g. TiCl₄) to square planar for some nickel complexes to octahedral for coordination complexes of cobalt. A range of transition metals can be found in biologically important compounds, such as iron in hemoglobin.

· Examples: iron pentacarbonyl, titanium tetrachloride, cisplatin

Organometallic compounds

Organolithium reagents are most often found in polymeric form, such as n-butyllithium.

Usually, organometallic compounds are considered to contain the M-C-H group. The metal (M) in these species can either be a main group element or a transition metal. Operationally, the definition of an organometallic compound is more relaxed to include also highly lipophilic complexes such as metal carbonyls and even metal alkoxides.

Organometallic compounds are mainly considered a special category because organic ligands are often sensitive to hydrolysis or oxidation, necessitating that organometallic chemistry employs more specialized preparative methods than was traditional in Werner-type complexes. Synthetic methodology, especially the ability to manipulate complexes in solvents of low coordinating power, enabled the exploration of very weakly coordinating ligands such as hydrocarbons, H₂, and N₂. Because the ligands are petrochemicals in some sense, the area of organometallic chemistry has greatly benefited from its relevance to industry.

· Examples: Cyclopentadienyliron dicarbonyl dimer (C₅H₅)Fe(CO)₂CH₃, Ferrocene Fe(C₅H₅)₂, Molybdenum hexacarbonyl Mo(CO)₆, Diborane B₂H₆, Tetrakis(triphenylphosphine)palladium(0) Pd[P(C₆H₅)₃]₄

I. Reading Exercises:

Exercise 1.Read and memorize using a dictionary:

rich coordination chemistry, square planar, nickel complexes, range of transition metals, organolithium reagents, metal carbonyls, sensitive to hydrolysis, solvent, preparative methods, weakly coordinating ligands

Exercise 2.Match the left part with the right:

1. A range of transition metals can be found	a) than was traditional in Werner-type complexes.
2. Compounds containing metals from group 4 to 11	b) in biologically important compounds.
3. Organometallic chemistry employs more specialized preparative methods	c) from its relevance to industry.
4. The area of organometallic chemistry has benefited	d) are considered transition metal compounds.

Exercise 3.Open brackets choosing the right words:

Transition metal compounds show a rich coordination chemistry (varying/choosing) from tetrahedral for titanium to (square/round) planar for some (nickel/ferrum) complexes to octahedral for coordination complexes of (iron/cobalt).

II. Speaking Exercises:

Exercise 1.Ask questions to the given answers:

1) Question: ___________________________________________ ?

Answer: Compounds with a metal from group 3 or 12 are sometimes also incorporated into this group, but also often classified as main group compounds.

2) Question: ___________________________________________ ?

Answer: Organolithium reagents are most often found in polymeric form, such as n-butyllithium.

3) Question: ___________________________________________ ?

Answer: Synthetic methodology enabled the exploration of very weakly coordinating ligands.

III. Writing Exercises:

Exercise 1.Complete the sentences with the suggested words: