Dari Wikipedia Indonesia, ensiklopedia bebas berbahasa Indonesia.
76 |
rhenium ← osmium → iridium |
Ru
↑
Os
↓
Hs |
|
|
Keterangan Umum Unsur |
Nama, Lambang, Nomor atom |
osmium, Os, 76 |
Seri kimia |
transition metals |
Golongan, Periode, Blok |
8, 6, d |
Penampilan |
silvery, blue cast
 |
Massa atom |
190.23(3) g/mol |
Konfigurasi elektron |
[Xe] 4f14 5d6 6s2 |
Jumlah elektron tiap kulit |
2, 8, 18, 32, 14, 2 |
Ciri-ciri fisik |
Fase |
solid |
Densitas (sekitar suhu kamar) |
22.61 g/cm³ |
Densitas cair pada titik lebur |
20 g/cm³ |
Titik lebur |
3306 K
(3033 °C, 5491 °F) |
Titik didih |
5285 K
(5012 °C, 9054 °F) |
Kalor peleburan |
57.85 kJ/mol |
Kalor penguapan |
738 kJ/mol |
Kapasitas kalor |
(25 °C) 24.7 J/(mol·K) |
Tekanan uap
P/Pa |
1 |
10 |
100 |
1 k |
10 k |
100 k |
pada T/K |
3160 |
3423 |
3751 |
4148 |
4638 |
5256 |
|
Ciri-ciri atom |
Struktur kristal |
hexagonal |
Bilangan oksidasi |
8, 6, 4, 2, -2
(mildly acidic oxide) |
Elektronegativitas |
2.2 (skala Pauling) |
Energi ionisasi |
pertama: 840 kJ/mol |
ke-2: 1600 kJ/mol |
Jari-jari atom |
130 pm |
Jari-jari atom (terhitung) |
185 pm |
Jari-jari kovalen |
128 pm |
Lain-lain |
Sifat magnetik |
? |
Electrical resistivity |
(0 °C) 81.2 nΩ·m |
Konduktivitas termal |
(300 K) 87.6 W/(m·K) |
Ekspansi termal |
(25 °C) 5.1 µm/(m·K) |
Kecepatan suara (pada wujud kawat) |
(20 °C) 4940 m/s |
Modulus rigiditas |
222 GPa |
Nisbah Poisson |
0.25 |
Modulus ruah |
462 GPa |
Skala kekerasan Mohs |
7.0 |
Kekerasan Brinell |
3920 MPa |
Nomor CAS |
7440-04-2 |
Isotop |
iso |
NA |
waktu paruh |
DM |
DE (MeV) |
DP |
184Os |
0.02% |
>5.6×1013y |
α |
2.966 |
180W |
185Os |
syn |
93.6 d |
ε |
1.013 |
185Re |
186Os |
1.58% |
2.0×1015y |
α |
2.822 |
182W |
187Os |
1.6% |
Os stabil dengan 111 neutron |
188Os |
13.3% |
Os stabil dengan 112 neutron |
189Os |
16.1% |
Os stabil dengan 113 neutron |
190Os |
24.6% |
Os stabil dengan 114 neutron |
191Os |
syn |
15.4 d |
β- |
0.314 |
191Ir |
192Os |
41.0% |
Os stabil dengan 116 neutron |
193Os |
syn |
30.11 d |
β- |
1.141 |
193Ir |
194Os |
syn |
6 y |
β- |
0.097 |
194Ir |
|
Referensi |
Osmium adalah suatu unsur kimia dalam tabel periodik yang memiliki lambang Os dan nomor atom 76. A hard brittle blue-gray or blue-black transition metal in the platinum family, osmium is the densest natural element and is used in some alloys with platinum and iridium. The extraordinary density of osmium is a consequence of the lanthanide contraction. Osmium is found native as an alloy in platinum ore and its tetroxide has been used to stain tissues and in fingerprinting. Alloys of osmium are employed in fountain pen tips, electrical contacts and in other applications where extreme durability and hardness are needed.