Metal nitrosyl compounds contain nitric oxide bonded as an NO+ ion, NO- ion, or neutral NO molecule. They can be classified into three classes based on the nitric oxide group present. Metal nitrosyls are coordination compounds where an NO molecule is attached as an NO+ ion to a metal atom or ion. Examples include metal nitrosyl carbonyls such as Co(NO+)(CO)3, metal nitrosyl halides such as Fe(NO+)2I, and metal nitrosyl thio-complexes involving Fe, Co, and Ni metals. These compounds can be prepared through the reaction of nitric oxide with metal compounds like carbonyls, halides, or ferrocyanides. Metal

1. Metal Nitrosyls and their
derivatives:
Subtitles:
 Definition.
 Classification
 Preparation
 Uses

2. Definition:
 Compounds that contain nitric oxide as NO+ ion, NO- ion or as
neutral molecule are known as nitrosyl compounds.
 Coordination compounds containing coordinated NO+ group
are called metal nitrosyls.
metal nitrosyl compound.

3. Structure:
 Studies shows that NOCl molecule is bent with N-O and N-Cl
bond distances equal to 1.14 Ao and 1.95 Ao respectively and
ONCl bond angle is equal to 115o.
 High value of dipole moment = 1.83 D measured in CCl4
suggest that N-Cl bond has some iconic character.
 Covalent structure of NOCl have V- shape which results from
sp2 hybridization.
N
O Cl

4. Classification of Nitrosyl Compounds:
 It can be classified into three classes:
I. Nitrosyl compounds containing NO+ group. e.g. Nitrosyl
halides.
II. Nitrosyl containing NO- group. e.g. Sodium nitrosyl Na[NO-
].
III. Coordination compounds containing coordinated NO+
group: metal nitrosyls

5. Metal Nitrosyls:
 Coordination compounds containing coordinated NO+
group: metal nitrosyls.
 Metal nitrosyls are coordinated compounds in which NO
molecule is attached as NO+ ion to a metal atom or ion.
 In these compounds NO+ ion which is known as nitrosonium
or nitrosyl cation acts as a ligand.
 The coordination compounds of transition metal containing
NO+ ion as ligand are called metal nitrosyls.

6. Examples of Metal Nitrosyls:
Metal Nitrosyl carbonyls:
Important examples of this
class re as follow: {Co(NO+)(CO)3} , {Mn-(NO+)(CO)4} etc.
Metal Nitrosyl Halides:
These compounds are
represented as: {Fe-(NO+)2I}2, {Fe(NO+)I}, {MI(NO+)X}, {Co-
(NO+)2X} etc.

7. Metal Nitrosyl Thio-complexes:
Coordinated
compounds are given by only Fe, Co and Ni. Examples are
M+{Fe-(NO+)2S}- etc.
Metal Nitrosyl Cyano complexes:
These complexes
are as follow: [Mn+(NO+)(CN)5]2-. Among these
[Fe(NO+)(CN)5]2- is most important.
Miscallaneous Metal Nitrosyls:
Nitrosyls like
[Co+(NO+)(NH3)5]2+, [Fe+(NO+)]2+ etc. are in this class.

8. Preparation:
 Metal Nitrosyl Carbonyls:
It can be prepared by the action
of NO on metal carbonyls.
Fe(CO)5 + 2NO Fe(CO)2(NO)2 + 3CO
Fe3(CO)12 + 6NO 3Fe(CO)2(NO)2 + 6CO
 Metal Nitrosyl Halides:
Prepared by the action of NO on
metal halides in the presence of suitable metal which acts as a
halogen acceptor.
2NiI2 + 2NO + Zn 2[Ni(NO)I] + ZnI2

9. CoX2 + 4NO + Co 2[Co(NO)2X]
Sodium Nitroprusside:
It can be prepared by warming a
solution of potassium ferrocyante with 50% HNO3 till a brown
solution is obtained.
K4[Fe(CN)6] + 4HNO3 H4[Fe(CN)6] + 4KNO3
H3[Fe(CN)6] + NO H2[Fe(NO)(CN)5] + HCN

10. USES:
 Metal nitrisyls are assumed to be intermediated in catalytic
converters.
 In biology nitric oxide is an important signalling molecule in
nature.
 Nitric oxide also attacks iron sulphur proteins giving dinitrosyl
iron complexes.

11. Thank You.