Thallium triiodide

Thallium(I) triiodide  Thallium triiodide

Names
IUPAC name

Thallium(I) triiodide

Other names

thallous triiodide

Identifiers

CAS Number

* 60488-29-1 Y
* 13453-37-7

3D model (JSmol)

* Interactive image

ChemSpider |

* 14888331

EC Number |

* 236-627-3

PubChem CID

* 20233350

CompTox Dashboard (EPA)

* DTXSID70928661

InChI

* InChI=1S/I3.Tl/c1-3-2;/q-1;+1

Key: CFEVJLSKLTWQJS-UHFFFAOYSA-N

SMILES

* [Tl+].I[I-]I

Properties

Chemical formula

| TlI3
Molar mass | 585.09 g·mol−1
Appearance  | black crystalline solid
Hazards
GHS labelling:

Pictograms

Signal word

| Danger

Hazard statements

| H300, H330, H373, H411
NFPA 704 (fire diamond)  |

Related compounds

Other cations

* Ammonium triiodide
* Rubidium triiodide
* Caesium triiodide

Related compounds

| Phosphorus heptabromide ([PBr4]+[Br3]−)

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)

Infobox references

Chemical compound

Thallium triiodide, more precisely thallium(I) triiodide is a chemical compound of thallium and iodine with empirical formula TlI3. Unlike the other thallium trihalides, which contain thallium(III), TlI3 is actually a thallium(I) salt containing thallium(I) cations Tl+ and triiodide anions [I3]−, and thus has the chemical formula Tl+[I3]−. It is a black crystalline solid.

An appreciation as to why Tl+ is not oxidised to Tl3+ in the reaction:

Tl3+ \+ 2 I− → Tl+ \+ I2

can be gained by considering the standard reduction potentials of the half-cells which are:

Tl3+ \+ 2 e− → Tl+; Er° = 1.252
I2 \+ 2 e− → 2 I−; Er° = 0.5355

The favoured reaction is therefore the reduction of Tl3+ to Tl+ (1.252 > 0.5355).

Using standard electrode potentials in this way must be done with caution as factors such as complex formation and solvation may affect the reaction. TlI3 is no exception as it is possible to stabilise thallium(III) with excess I− forming the tetraiodothallate(III) ion [TlI4]− (isoelectronic with the tetraiodomercurate anion [HgI4]2− and with lead(IV) iodide PbI4).

## Structure and preparation

[edit]

TlI3 is formulated Tl+[I3]−, and has a similar structure to NH4I3, CsI3 and RbI3.[1] The triiodide ion in TlI3 is nearly linear but is asymmetric with one iodine-iodine bond longer than the other. For comparison the dimensions of the triiodide, Ia-Ib-Ic, ions in the different compounds are shown below:

compound  | Ia-Ib (pm)  | Ib-Ic (pm)  | angle (°)

|
|
|

TlI3 | 306.3  | 282.6  | 177.90
RbI3 | 305.1  | 283.3  | 178.11
CsI3 | 303.8  | 284.2  | 178.00
NH4I3 | 311.4  | 279.7  | 178.55

TlI3 can be prepared by the evaporation of stoichiometric quantities of thallium(I) iodide (TlI) and iodine in concentrated aqueous hydriodic acid, or by reacting TlI with iodine in ethanol.

## References

[edit]

* WebElements
* Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

1. ^ Tebbe, K.F.; Georgy, U. (1985-12-15). "Die Kristallstrukturen von Rubidiumtriiodid und Thalliumtriiodid". Acta Crystallographica C (in German). 42 (12): 1675–1678\. doi:10.1107/S0108270186090972.

* v
* t
* e

Thallium compounds

Neg. ox. states|

* Thallides

Thallium(I)|

* TlN3
* TlOH
* TlI
* TlBr
* Tl2CO3
* TlCl
* TlF
* TlPF6
* TlNO3
* Tl2O
* Tl2SO4
* Tl2S
* Tl2Te
* TlI3
* TBCCO

| Organothallium(I)|

* TlC2H3O2
* Tl2C3H2O4
* TlC5H5

|

Thallium(III)|

* TlH3
* Tl(OH)3
* Tl2O3
* Tl(NO3)3
* Tl(CH3COO)3
* TlF3
* Tl(CF3COO)3

* v
* t
* e

Salts and covalent derivatives of the iodide ion

| HI
+H |  |  |  | He

|
|
|
|

LiI | BeI2 | BI3
+BO3 | CI4
+C | NI3
NH4I
+N | I2O4
I2O5
I2O6
I4O9 | IF
IF3
IF5
IF7 | Ne
NaI | MgI2 | AlI
AlI3 | SiI4 | PI3
P2I4

PI5 | S2I2 | ICl
ICl3 | Ar
KI | CaI2 |  | ScI3 | TiI2
TiI3
TiI4 | VI2
VI3 | CrI2
CrI3
CrI4 | MnI2 | FeI2
FeI3 | CoI2 | NiI2
-Ni | CuI | ZnI2 | GaI
GaI3 | GeI2
GeI4
+Ge | AsI3
As2I4
+As | Se  | IBr
IBr3 | Kr
RbI
RbI3 | SrI2 |  | YI3 | ZrI2
ZrI3
ZrI4 | NbI4
NbI5 | MoI2
MoI3 | TcI3 | RuI3 | RhI3 | PdI2 | AgI | CdI2 | InI
InI3 | SnI2
SnI4 | SbI3
+Sb | TeI4
+Te | I−

3 | Xe
CsI
CsI3 | BaI2 |  | LuI3 | HfI3
HfI4 | TaI4
TaI5 | WI2
WI3
WI4 | ReI3
ReI
4 | OsI
OsI2
OsI3 | IrI3
IrI
4 | PtI2
PtI4 | AuI
AuI3 | Hg2I2
HgI2 | TlI
TlI3 | PbI2 | BiI3 | PoI2
PoI4 | AtI | Rn
Fr  | RaI2 |  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og
| ↓  |  |
| LaI2
LaI3 | CeI2
CeI3 | PrI2
PrI3 | NdI2
NdI3 | PmI3 | SmI2
SmI3 | EuI2
EuI3 | GdI2
GdI3 | TbI3 | DyI2
DyI
3 | HoI3 | ErI3 | TmI2
TmI3 | YbI2
YbI3
AcI3 | ThI2
ThI3
ThI4 | PaI4
PaI5 | UI3
UI4 | NpI3 | PuI3 | AmI2
AmI3 | CmI3 | BkI
3 | CfI

CfI
3 | EsI2
EsI3 | Fm  | Md  | No
*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H300]: H300: Fatal if swallowed
*[H330]: H330: Fatal if inhaled
*[H373]: H373: May cause damage to organs through prolonged or repeated exposure
*[H411]: H411: Toxic to aquatic life with long lasting effects
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