性 状：    分轻质和重质两种。轻质体积蓬松，为白色无定形粉末。无嗅无味无毒。难溶于纯水及有机溶剂，在水中溶解度因二氧化碳的存在而增大。能溶于酸、铵盐溶液。经高温灼烧转化为结晶体。遇空气中的二氧化碳生成碳酸镁复盐。重质体积紧密，为白色或米黄色粉末。与水易化合，露置空气中易吸收水分和二氧化碳。与氯化镁溶液混合易胶凝硬化。
密度：3．58
熔点：2852℃
沸点：3600℃

质量标准：
GB/T 9857-88
项目Item                        分析纯     化学纯
(AR)       (CP)
含量(MgO)Assay,%                     ≥ 98.0        97.0
澄清度试验Clarity                      合格        合格
盐酸不溶物Insoluble matter           ≤ 0.01        0.05
in hydrochlorie acid,%
水溶物Soluble matter,%               ≤ 0.5          --
灼烧失重Ignition loss,%              ≤ 2.0         3.0
氯化物(Cl)Chloride,%                 ≤ 0.01        0.03
硫酸盐(SO4)Sulfate,%                 ≤ 0.02        0.1
磷酸盐(PO4)Phosphate,%               ≤ 0.003       0.01
总氮量(N)Total nitrogen,%            ≤ 0.001       0.003
碳酸盐(以CO2计)Carbonate,%           ≤ 1.5          --
钠(Na)Sodium,%                       ≤ 0.05        0.1
钾(K)Potassium,%                    ≤ 0.005       0.01
钙(Ca)Calcium,%                      ≤ 0.02        0.1
铁(Fe)Iron,%                         ≤ 0.005       0.01
铜(Cu)Copper,%                       ≤ 0.001       --
锌(Zn)Zinc,%                         ≤ 0.005       0.01
砷(As)Arsenic,%                      ≤ 0.0001      --
钡和锶(以Ba计)Barium and strontium,% ≤ 0.005       0.01
重金属(以Pb计)Heavy metals,%         ≤ 0.003       0.01

高纯氧化镁粉（99.99%）：

纯度Purity                              ≥99.99%
不纯物含量(ug/g）：
Ca                                      ≤10
Fe                                      ≤10
Na                                      ≤5
Si                                      ≤15
B                                       ≤5
K                                       ≤0.5
Al                                      ≤10
S                                       ≤5
Clˉ                                    ≤150
粒径                                    40μm
比表面积                                0.759 m2/g
煅烧温度                                950℃

晶体氧化镁：

晶体结构Physical form ：                立方体 a=4.216埃（cubic a = 4.216 ?)
生长方法：                              电弧熔融法
熔    点mp:                             2852℃
晶体纯度assay(MgO)                      >99.95%
晶体解理面：
尺寸size                                10 mm × 10 mm × 0.5 mm
密度Density：                           3.58g/cm3
介电常数dielectric constant:            9.8
热膨胀系数Thermal expansion:            12.8×10 -6/℃
光透过率transmittance:                  200-400 nm, >90%
500-1000 nm, >98%
总杂质total impurities：
C                                       <10 ppm
Cr                                      <10 ppm
Si                                      <10 ppm
Al                                      <15 ppm
Ca