Silicon dioxide

Melting point :>1600 °C(lit.)
Boiling point :>100 °C(lit.)
bulk density :200-800kg/m3
Density :2.2-2.6 g/mL at 25 °C
vapor pressure :13.3hPa at 1732℃
refractive index :1.46
Flash point :2230°C
storage temp. :2-8°C
solubility :Practically insoluble in water and in mineral acids except hydrofluoric acid. It dissolves in hot solutions of alkali hydroxides.
pka :6.65-9.8[at 20 ℃]
form :suspension
Specific Gravity :2.2
color :White to yellow
PH :5-8 (100g/l, H2O, 20℃)(slurry)
Odor :at 100.00?%. odorless
Resistivity :1∞10*20 (ρ/μΩ.cm)
Water Solubility :insoluble
Sensitive :Hygroscopic
Hydrolytic Sensitivity :6: forms irreversible hydrate
Crystal Structure :Trigonal
Merck :14,8493
Exposure limits :NIOSH: IDLH 3000 mg/m3; TWA 6 mg/m3
Stability :Stable.
CAS DataBase Reference :7631-86-9(CAS DataBase Reference)
IARC :3 (Vol. Sup 7, 68) 1997
NIST Chemistry Reference :Silicon(iv) oxide(7631-86-9)
EPA Substance Registry System :Silica (7631-86-9)
ECETOC JACC REPORT :Silicon dioxide (7631-86-9)

Symbol(GHS):
Signal word:	Warning
Hazard statements:	Code Hazard statements Hazard class Category Signal word Pictogram P-Codes H317 May cause an allergic skin reaction Sensitisation, Skin Category 1 Warning P261, P272, P280, P302+P352,P333+P313, P321, P363, P501 H412 Harmful to aquatic life with long lasting effects Hazardous to the aquatic environment, long-term hazard Category 3 P273, P501
Precautionary statements:	P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P272 Contaminated work clothing should not be allowed out of the workplace. P273 Avoid release to the environment. P280 Wear protective gloves/protective clothing/eye protection/face protection. P302+P352 IF ON SKIN: wash with plenty of soap and water. P333+P313 IF SKIN irritation or rash occurs: Get medical advice/attention.