摘要
西盟石产于云南省西盟锡矿区,为低温热液交代产物,与磷铝铋石等共生。西盟石呈无色土状、变胶状、不规则粒状集合体,六方晶系,一轴晶正光性,N>1.78,H_v=279-283kg/cm^2,D_c=5.534g/cm^3(干晶体),电子束下发黄绿色荧光。经电子探针定量分析,西盟石成分为:Bi_2O_376.34％,P_2O_522.92％。计算的化学式为:Bi_(1.01)P_(0.99)O_4,简化为BiPO_4。西盟石的X射线衍射分析较强线为:6.052(100)(73),4.420(101)(91),3.493(110)(88),3.024(200)(100),2.854(102)(65)。计算的晶胞参数为:a=6.9860A(16),c=6.4753A(28),V=273.68A^3Z=3,空间群为P3_121。文中还与人工合成的西盟石作了某些对比。
The new mineral-ximengite occurs in the Ximen tin mining district ab-out 420km southwest of Kunming, Yunnan Province. Ximengite occurs as earthy aggregates of irregular microcrystals. Colourle-ss, white streak, oily to vitreous lustre, transparent to translucent. VHN=281(279-283)kg/cm^2. Brittle. Density(calc.) = 5. 534 g/cm^3(dry crystals). Fluore-scent effect: yellowish green under electron probe. Electron analysis of ximengite gave: Bi_2O_3 76.34% and P_2O_5 22.92%, tot-aling 99.26 wt.%. The empirical formula (based on 4 oxygen ions) is: Bi_(1.01)P_(0.99)O_(4.00), The simplified formula is BiPO_4. The strongest lines are: 6.052(73) (100), 4. 4198(91) (101), 3. 4930(88) (110),3.0244(100) (200) and 2.8537(65) (102). Space group P3_121; α= 6.986(2), c=6.475(2)A, V=273.68A^3, Z=3. In the study, the mineral was compared withsynthetic ximengite as well.
出处
《矿物学报》
CAS
CSCD
北大核心
1989年第1期15-19,99,共5页
Acta Mineralogica Sinica
关键词
西盟石
新矿物
ximengite
new mineral
Yunnan
