Lithium disilicate

Lithium disilicate (Li₂Si₂O₅) is a chemical compound that is a glass ceramic. They are widely used as dental ceramics due to their strength, machinability, and translucency.

Lithium disilicate

Names
IUPAC name Lithium disilicate
Identifiers
CAS Number	66402-68-4[1]
3D model (JSmol)	Interactive image
EC Number	266-340-9
PubChem CID	101943115
InChI InChI=1S/2Li.O5Si2/c;;1-6(2)5-7(3)4/q2*+1;-2 Key: WVMPCBWWBLZKPD-UHFFFAOYSA-N
SMILES [Li+].[Li+].[O-][Si](=O)O[Si](=O)[O-]
Properties
Chemical formula	Li2O5Si2
Molar mass	150.04 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Use

Lithium disilicate has found applications in dentistry as a material for crowns in the form of Li₂Si₂O₅. Lithium disilicate has an unusual microstructure that consists of many randomly oriented small and interlocking plate-like needle-like crystals. This structure causes cracks to be deflected, blunted, and/or to branch, which prevents cracks from growing.[2] Lithium disilicate has a biaxial flexible strength in the range of 360 MPa to 400 MPa; in comparison, for metal ceramics this is around 80 to 100 MPa, for veneered zirconia it's approximately 100 MPa, and for leucite glass ceramic it's approximately 150 to 160 MPa. It has high hardness (5.92 +/- 0.18 GPa) and fracture toughness (3.3 +/- 0.14 MPa m^1/2). In addition, it can be made to have an appearance that very closely resembles that of natural human teeth.

Lithium disilicate is also used as a non-conductive seal, enamel or feed-through insulator in nickel superalloys or stainless steel, as it has a high thermal expansion.[3][4]

References

1. Ivoclar Vivadent AG (8 November 2012). "Safety data sheet" (PDF). Retrieved 2 March 2020.
2. Shenoy A, Shenoy N (2010). "Dental ceramics: An update". J Conserv Dent. 13 (4): 195–203. doi:10.4103/0972-0707.73379. PMC 3010023. PMID 21217946.
3. Holand, Wolfram; Beall, George H. (2019). Glass-Ceramic Technology. John Wiley & Sons. ISBN 978-1-119-42369-0.
4. Dai, Steve. "Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part I: screening of doping oxidants". OSTI. Retrieved 2 March 2020.