Gadolinium(III) chloride

Gadolinium(III) chloride  |  |

|

Names
IUPAC name

Gadolinium(III) chloride

Other names

Gadolinium trichloride
Gadolinium chloride

Identifiers

CAS Number

* 10138-52-0 Y
* 19423-81-5 (hexahydrate) N

3D model (JSmol)

* Interactive image

ChEBI |

* CHEBI:37288 Y

ChEMBL |

* ChEMBL1697696 N

ChemSpider |

* 55406 Y

PubChem CID

* 61486

UNII |

* P7082WY76D Y

InChI

* InChI=1S/3ClH.Gd/h3*1H;/q;;;+3/p-3 Y

Key: MEANOSLIBWSCIT-UHFFFAOYSA-K Y

* InChI=1/3ClH.Gd/h3*1H;/q;;;+3/p-3

Key: MEANOSLIBWSCIT-DFZHHIFOAP

SMILES

* Cl[Gd](Cl)Cl

Properties

Chemical formula

| GdCl3
Molar mass | 263.61 g/mol
Appearance  | white crystals
hygroscopic
Density | 4.52 g/cm3
Melting point |  609 °C (1,128 °F; 882 K)
Boiling point |  1,580 °C (2,880 °F; 1,850 K)

Solubility in water

| 94.65 g/100mL, 25°C[1]

Magnetic susceptibility (χ)

| +27,930·10−6 cm3/mol
Structure

Crystal structure

| hexagonal, hP8

Space group

| P63/m, No. 176
Related compounds

Other anions

| Gadolinium(III) fluoride
Gadolinium(III) bromide
Gadolinium(III) oxide

Other cations

| Europium(III) chloride
Terbium(III) chloride

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

N verify (what is YN ?)
Infobox references

Gadolinium(III) chloride, also known as gadolinium trichloride, is GdCl3. It is a colorless, hygroscopic, water-soluble solid. The hexahydrate GdCl3∙6H2O is commonly encountered and is sometimes also called gadolinium trichloride. Gd3+ species are of special interest because the ion has the maximum number of unpaired spins possible, at least for known elements. With seven valence electrons and seven available f-orbitals, all seven electrons are unpaired and symmetrically arranged around the metal. The high magnetism and high symmetry combine to make Gd3+ a useful component in NMR spectroscopy and MRI.

## Contents

* 1 Preparation
* 2 Structure
* 3 Properties, with applications to MRI
* 4 References

## Preparation

GdCl3 is usually prepared by the "ammonium chloride" route, which involves the initial synthesis of (NH4)2[GdCl5]. This material can be prepared from the common starting materials at reaction temperatures of 230 °C from gadolinium oxide:[2]

10 NH4Cl + Gd2O3 → 2 (NH4)2[GdCl5] + 6 NH3 \+ 3 H2O

from hydrated gadolinium chloride:

4 NH4Cl + 2 GdCl3∙6H2O → 2 (NH4)2[GdCl5] + 12 H2O

from gadolinium metal:

10 NH4Cl + 2 Gd → 2 (NH4)2[GdCl5] + 6 NH3 \+ 3 H2

In the second step the pentachloride is decomposed at 300 °C:

(NH4)2[GdCl5] → GdCl3 \+ 2 NH4Cl

This pyrolysis reaction proceeds via the intermediacy of NH4[Gd2Cl7].

The ammonium chloride route is more popular and less expensive than other methods. GdCl3 can, however, also be synthesized by the reaction of solid Gd at 600 °C in a flowing stream of HCl.[3]

Gd + 3 HCl → GdCl3 \+ 3/2 H2

Gadolinium(III) chloride also forms a hexahydrate, GdCl3∙6H2O. The hexahydrate is prepared by gadolinium(III) oxide (or chloride) in concentrated HCl followed by evaporation.[4]

## Structure

GdCl3 crystallizes with a hexagonal UCl3 structure, as seen for other 4f trichlorides including those of La, Ce, Pr, Nd, Pm, Sm, Eu.[5] The following crystallize in theYCl3 motif: DyCl3, HoCl3, ErCl3, TmCl3, YdCl3, LuCl3, YCl3). The UCl3 motif features 9-coordinate metal with a tricapped trigonal prismatic coordination sphere. In the hexahydrate of gadolinium(III) chloride and other smaller 4f trichlorides and tribromides, six H2O molecules and 2 Cl− ions coordinate to the cations resulting in a coordination group of 8.

## Properties, with applications to MRI

Gadolinium salts are of primary interest for relaxation agents in magnetic resonance imaging (MRI). This technique exploits the fact that Gd3+ has an electronic configuration of f7. Seven is the largest number of unpaired electron spins possible for an atom, so Gd3+ is a key component in the design of highly paramagnetic complexes.[6] To generate the relaxation agents, Gd3+ sources such as GdCl3∙6H2O are converted to coordination complexes. GdCl3∙6H2O can not be used as an MRI contrasting agent due to its low solubility in water at the body's near neutral pH.[7] "Free" gadolinium(III), e.g. [GdCl2(H2O)6]+, is toxic, so chelating agents are essential for biomedical applications. Simple monodentate or even bidentate ligands will not suffice because they do not remain bound to Gd3+ in solution. Ligands with higher coordination numbers therefore are required. The obvious candidate is EDTA4−, ethylenediaminetetraacetate, which is a commonly employed hexadentate ligand used to complex to transition metals. In lanthanides, however, exhibit coordination numbers greater than six, so still larger aminocarboxylates are employed.

One representative chelating agent is H5DTPA, diethylenetriaminepentaacetic acid.[8] Chelation to the conjugate base of this ligand increases the solubility of the Gd3+ at the body's neutral pH and still allows for the paramagnetic effect required for an MRI contrast agent. The DTPA5− ligand binds to Gd through five oxygen atoms of the carboxylates and three nitrogen atoms of the amines. A 9th binding site remains, which is occupied by a water molecule. The rapid exchange of this water ligand with bulk water is a major reason for the signal enhancing properties of the chelate. The structure of [Gd(DTPA)(H2O)]2− is a distorted tricapped trigonal prism.

The following is the reaction for the formation of Gd-DTPA:

## References

1. ↑ Saeger, Victor William; Spedding, F. H. (November 1960). Some physical properties of rare-earth chlorides in aqueous solution. Ames Laboratory Technical Reports 46. p. 38. https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1043&context=ameslab_isreports. Retrieved 19 October 2020.
2. ↑ Meyer, G. (1989). The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides-The Example of YCl3. Inorganic Syntheses. 25. pp. 146–150. doi:10.1002/9780470132562.ch35. ISBN 978-0-470-13256-2.
3. ↑ Corbett, John D. (1983). "Trichlorides of the Rare Earth Elements, Yttrium, and Scandium". Inorganic Syntheses. Inorganic Syntheses. 22. pp. 39–42. doi:10.1002/9780470132531.ch8. ISBN 978-0-470-13253-1.
4. ↑ Quill, L. L.; Clink, George L. (1967). "Preparation of Lanthanide Chloride Methanolates Using 2,2-Dimethoxypropane". Inorganic Chemistry 6 (7): 1433–1435. doi:10.1021/ic50053a032.
5. ↑ Wells, A.F. (1984). Structural Inorganic Chemistry. Oxford: Clarendon Press.
6. ↑ Raduchel, B.; Weinmann, H.; Muhler, A. (1996). "Gadolinium Chelates: Chemistry, Safety, & Behavior". Encyclopedia of Nuclear Magnetic Resonance 4: 2166–2172.
7. ↑ Spencer, A. J.; Wilson, S. A.; Batchelor, J.; Reid, A.; Pees, J.; Harpur, E. (1997). "Gadolinium Chloride Toxicity in the Rat". Toxicologic Pathology 25 (3): 245–255. doi:10.1177/019262339702500301. ISSN 0192-6233. PMID 9210255.
8. ↑ Aime, S.; Botta, Mauro; Dastru, Walter; Fasano, Mauro; Panero, Maurizio; Arnelli, Aldo (1993). "Synthesis and Characterization of a Novel DPTA-like Gadolinium(III) Complex: A Potential Reagent for the Determination of Glycated Proteins by Water Proton NMR Relaxation Measurements". Inorganic Chemistry 32 (10): 2068–2071. doi:10.1021/ic00062a031.

* "Gadolinium". Magnetic Resonance TIP-MRI Database. http://www.mr-tip.com/serv1.php?type=db1&dbs=Gadolinium.
* "Gadolinium". Webelements. http://www.webelements.com/webelements/compounds/text/Gd/Cl3Gd1-10138520.html.

* v
* t
* e

Gadolinium compounds

Gadolinium(III)|

* GdF3
* GdCl3
* GdBr3
* Gd2O3
* Gd2O2S
* Gd2(SO4)3
* Gd(NO3)3
* Gd2(C2O4)3
* Gd3Ga5O12
* Gd2SiO5

| Organogadolinium(III)|

* Gd(C5H7O2)3

|

* v
* t
* e

Salts and covalent derivatives of the chloride ion

HCl |  |  |  | He

|
|
|
|

LiCl | BeCl2 | BCl3
B2Cl4 | CCl4 | NCl3
ClN3 | Cl2O
ClO2
Cl2O7 | ClF
ClF3
ClF5 | Ne
NaCl | MgCl2 | AlCl
AlCl3 | SiCl4 | P2Cl4
PCl3
PCl5 | S2Cl2
SCl2
SCl4 | Cl2 | Ar
KCl | CaCl
CaCl2 | ScCl3 | TiCl2
TiCl3
TiCl4 | VCl2
VCl3
VCl4
VCl5 | CrCl2
CrCl3
CrCl4 | MnCl2 | FeCl2
FeCl3 | CoCl2
CoCl3 | NiCl2 | CuCl
CuCl2 | ZnCl2 | GaCl2
GaCl3 | GeCl2
GeCl4 | AsCl3
AsCl5 | Se2Cl2
SeCl4 | BrCl | KrCl
RbCl | SrCl2 | YCl3 | ZrCl3
ZrCl4 | NbCl4
NbCl5 | MoCl2
MoCl3
MoCl4
MoCl5
MoCl6 | TcCl4 | RuCl3 | RhCl3 | PdCl2 | AgCl | CdCl2 | InCl
InCl2
InCl3 | SnCl2
SnCl4 | SbCl3
SbCl5 | Te3Cl2
TeCl4 | ICl
ICl3 | XeCl
XeCl2
CsCl | BaCl2 |  | HfCl4 | TaCl5 | WCl2
WCl3
WCl4
WCl5
WCl6 | Re3Cl9
ReCl4
ReCl5
ReCl6 | OsCl4 | IrCl2
IrCl3
IrCl4 | PtCl2
PtCl4 | AuCl
AuCl3 | Hg2Cl2,
HgCl2 | TlCl | PbCl2,
PbCl4 | BiCl3 | PoCl2,
PoCl4 | AtCl  | RnCl2
FrCl | RaCl2 |  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og
| ↓  |  |
LaCl3 | CeCl3 | PrCl3 | NdCl2,
NdCl3 | PmCl3 | SmCl2,
SmCl3 | EuCl2,
EuCl3 | GdCl3 | TbCl3 | DyCl2,
DyCl3 | HoCl3 | ErCl3 | TmCl2
TmCl3 | YbCl2
YbCl3 | LuCl3
AcCl3 | ThCl4 | PaCl5 | UCl3
UCl4
UCl5
UCl6 | NpCl4 | PuCl3 | AmCl2
AmCl3 | CmCl3 | BkCl3 | CfCl3 | EsCl3 | Fm  | Md  | No  | LrCl3

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Gadolinium(III) chloride. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Gadolinium(III)_chloride&oldid=560482"
*[CID]: Compound ID
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template