What is Calcium oxide?
{{chembox | Name = Calcium oxide | ImageFile = Oxid vápenatý.PNG | ImageName = Calcium oxide | ImageFile1 = Calcium oxide.JPG | IUPACName = Calcium oxide | OtherNames = Quicklime, burnt lime, unslaked lime, pebble lime, calcia | Section1 = {{Chembox Identifiers | ChemSpiderID = 14095 | UNII = C7X2M0VVNH | InChI = 1/Ca.O/rCaO/c1-2 | SMILES = [Ca]=O | ChEBI = 31344 | ChEMBL = 2104397 | InChIKey = ODINCKMPIJJUCX-BFMVISLHAU | CASNo = 1305-78-8 | PubChem = 14778 | RTECS = EW3100000 | UNNumber = 1910 | Gmelin = 485425 }} | Section2 = {{Chembox Properties | Formula = CaO | MolarMass = 56.0774{{nbsp}}g/mol | Appearance = White to pale yellow/brown powder | Odor = Odorless | Density = 3.34{{nbsp}}g/cm<sup>3</sup><ref name=crc/> | Solubility = Reacts to form [[calcium hydroxide]] | MeltingPtC = 2613 | MeltingPt_ref = <ref name=crc>{{RubberBible92nd|page=4.55}}</ref> | BoilingPtC = 2850 | BoilingPt_notes = (100{{nbsp}}[[hPa]])<ref name=r1>[http://gestis.itrust.de/nxt/gateway.dll/gestis_de/001200.xml?f=templates$fn=default.htm$3.0 Calciumoxid] {{webarchive|url=https://web.archive.org/web/20131230232501/http://gestis.itrust.de/nxt/gateway.dll/gestis_de/001200.xml?f=templates%24fn%3Ddefault.htm%243.0 |date=2013-12-30 }}. GESTIS database</ref> | pKa = 12.8 | Solvent2 = Methanol | Solubility2 = Insoluble (also in [[diethyl ether]], [[octanol]]) | MagSus = −15.0×10<sup>−6</sup>{{nbsp}}cm<sup>3</sup>/mol }} | Section3 = {{Chembox Structure | CrystalStruct = [[Cubic crystal system|Cubic]], [[Pearson symbol|cF8]] }} | Section4 = | Section5 = {{Chembox Thermochemistry | DeltaHf = −635&nbsp;kJ·mol<sup>−1</sup><ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles 6th Ed.| url = https://archive.org/details/chemicalprincipl0000zumd_u9g0| publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A21}}</ref> | Entropy = 40&nbsp;J·mol<sup>−1</sup>·K<sup>−1</sup><ref name=b1 /> }} | Section6 = {{Chembox Pharmacology | ATCvet = yes | ATCCode_prefix = P53 | ATCCode_suffix = AX18 }} | Secti