{{위키데이터 속성 추적}}
'''[[세슘]]'''은 원자량 112~151 사이에 총 40개의 [[동위 원소]]가 알려져 있으며, [[안정 동위 원소]]는 <sup>133</sup>Cs 한 가지 뿐이다. 가장 안정한 [[방사성 동위 원소]]는 약 230만 년의 [[반감기]]를 갖는 <sup>135</sup>Cs, 30.1671년의 반감기를 갖는 <sup>137</sup>Cs, 2.0652년의 반감기를 갖는 <sup>134</sup>Cs 등이다. 이외의 동위 원소들은 모두 반감기가 14일 미만이며, 대부분은 1시간 미만이다.

세슘의 표준 원자량은 132.9054519(2) [[원자량 단위|u]]이다.

== 세슘-133 ==
<sup>133</sup>Cs은 세슘 동위 원소 중 유일하게 안정한 천연 동위 원소이다. [[원자로]]에서 [[방사성 붕괴]]의 산물로 생성되기도 한다. <sup>133</sup>Cs 원자핵은 1초에 9,192,631,770번 진동하는데, 이를 이용하여 [[국제원자시]]의 1초를 정의한다.

== 세슘-137 ==
{{본문|세슘-137}}
<sup>137</sup>Cs은 30.17년의 [[반감기]]를 갖는 동위 원소로, [[스트론튬-90|<sup>90</sup>Sr]]과 함께 [[사용후 핵연료]]에서 다량 생성된다. 자연계에서는 우라늄과 토륨의 [[자발 핵분열]]의 생성물로 극미량이 형성되었다가 사라졌다를 반복하고 있다.

<sup>137</sup>Cs은 [[베타 붕괴]]하여 <sup>137m</sup>[[바륨|Ba]]으로 붕괴하였다가 다시 안정 동위 원소인 <sup>137</sup>Ba로 붕괴하는데, 이 과정에서 강력한 [[감마선]]을 방출한다.

흔히 원전이 폭발할 때 나오는 [[세슘]] 동위원소이다.

[[스트론튬-90|<sup>90</sup>Sr]]과 함께 나온다.



== 표 ==
{| class="wikitable" style="font-size:95%; white-space:nowrap"
! rowspan="2" | 핵종<br />기호
! Z([[양성자|p]])
! N([[중성자|n]])
! &nbsp;<br />동위 원소 질량 (u)<br />&nbsp;
! rowspan="2" | 반감기
! rowspan="2" | 붕괴<br />방식<ref>http://www.nucleonica.net/unc.aspx</ref><ref group="n">약자:<br>ε: [[전자 포획]]<br>IT: [[이성질핵 전이]]</ref>
! rowspan="2" | 붕괴<br />생성물<ref group="n">굵은 글꼴은 안정 동위 원소, 굵은 이탤릭체 글꼴은 거의 안정하여 반감기가 [[우주의 나이]]보다 긴 동위 원소</ref>
! rowspan="2" | 핵<br />스핀
! rowspan="2" | 자연적<br />동위 원소<br />구성비<br />(몰 분율)
! rowspan="2" | 자연적<br />구성비<br />변동 범위<br />(몰 분율)
|-
! colspan="3" | 들뜬 에너지
|-
| rowspan=2|<sup>112</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 57
| rowspan=2|111.95030(33)#
| rowspan=2|500(100) µs
| [[양성자 방출|p]]
| <sup>111</sup>Xe
| rowspan=2|1+#
| rowspan=2|
| rowspan=2|
|-
| [[알파 붕괴|α]]
| <sup>108</sup>I
|-
| rowspan=2|<sup>113</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 58
| rowspan=2|112.94449(11)
| rowspan=2|16.7(7) µs
| p (99.97%)
| <sup>112</sup>Xe
| rowspan=2|5/2+#
| rowspan=2|
| rowspan=2|
|-
| [[베타 붕괴|β<sup>+</sup>]] (0.03%)
| <sup>113</sup>Xe
|-
| rowspan=4|<sup>114</sup>Cs
| rowspan=4 style="text-align:right" | 55
| rowspan=4 style="text-align:right" | 59
| rowspan=4|113.94145(33)#
| rowspan=4|0.57(2) s
| β<sup>+</sup> (91.09%)
| <sup>114</sup>Xe
| rowspan=4|(1+)
| rowspan=4|
| rowspan=4|
|-
| β<sup>+</sup>, p (8.69%)
| <sup>113</sup>I
|-
| β<sup>+</sup>, α (0.19%)
| <sup>110</sup>Te
|-
| α (0.018%)
| <sup>110</sup>I
|-
| rowspan=2|<sup>115</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 60
| rowspan=2|114.93591(32)#
| rowspan=2|1.4(8) s
| β<sup>+</sup> (99.93%)
| <sup>115</sup>Xe
| rowspan=2|9/2+#
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, p (0.07%)
| <sup>114</sup>I
|-
| rowspan=3|<sup>116</sup>Cs
| rowspan=3 style="text-align:right" | 55
| rowspan=3 style="text-align:right" | 61
| rowspan=3|115.93337(11)#
| rowspan=3|0.70(4) s
| β<sup>+</sup> (99.67%)
| <sup>116</sup>Xe
| rowspan=3|(1+)
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, p (0.279%)
| <sup>115</sup>I
|-
| β<sup>+</sup>, α (0.049%)
| <sup>112</sup>Te
|-
| rowspan=3 style="text-indent:1em" | <sup>116m</sup>Cs
| rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
| rowspan=3|3.85(13) s
| β<sup>+</sup> (99.48%)
| <sup>116</sup>Xe
| rowspan=3|4+,5,6
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, p (0.51%)
| <sup>115</sup>I
|-
| β<sup>+</sup>, α (0.008%)
| <sup>112</sup>Te
|-
| <sup>117</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 62
| 116.92867(7)
| 8.4(6) s
| β<sup>+</sup>
| <sup>117</sup>Xe
| (9/2+)#
|
|
|-
| style="text-indent:1em" | <sup>117m</sup>Cs
| colspan="3" style="text-indent:2em" | 150(80)# keV
| 6.5(4) s
| β<sup>+</sup>
| <sup>117</sup>Xe
| 3/2+#
|
|
|-
| rowspan=3|<sup>118</sup>Cs
| rowspan=3 style="text-align:right" | 55
| rowspan=3 style="text-align:right" | 63
| rowspan=3|117.926559(14)
| rowspan=3|14(2) s
| β<sup>+</sup> (99.95%)
| <sup>118</sup>Xe
| rowspan=3|2
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, p (0.042%)
| <sup>117</sup>I
|-
| β<sup>+</sup>, α (0.0024%)
| <sup>114</sup>Te
|-
| rowspan=3 style="text-indent:1em" | <sup>118m</sup>Cs
| rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
| rowspan=3|17(3) s
| β<sup>+</sup> (99.95%)
| <sup>118</sup>Xe
| rowspan=3|(7-)
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, p (0.042%)
| <sup>117</sup>I
|-
| β<sup>+</sup>, α (0.0024%)
| <sup>114</sup>Te
|-
| rowspan=2|<sup>119</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 64
| rowspan=2|118.922377(15)
| rowspan=2|43.0(2) s
| β<sup>+</sup>
| <sup>119</sup>Xe
| rowspan=2|9/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, α (2×10<sup>−6</sup>%)
| <sup>115</sup>Te
|-
| style="text-indent:1em" | <sup>119m</sup>Cs
| colspan="3" style="text-indent:2em" | 50(30)# keV
| 30.4(1) s
| β<sup>+</sup>
| <sup>119</sup>Xe
| 3/2(+)
|
|
|-
| rowspan=3|<sup>120</sup>Cs
| rowspan=3 style="text-align:right" | 55
| rowspan=3 style="text-align:right" | 65
| rowspan=3|119.920677(11)
| rowspan=3|61.2(18) s
| β<sup>+</sup>
| <sup>120</sup>Xe
| rowspan=3|2(-#)
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, α (2×10<sup>−5</sup>%)
| <sup>116</sup>Te
|-
| β<sup>+</sup>, p (7×10<sup>−6</sup>%)
| <sup>118</sup>I
|-
| rowspan=3 style="text-indent:1em" | <sup>120m</sup>Cs
| rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
| rowspan=3|57(6) s
| β<sup>+</sup>
| <sup>120</sup>Xe
| rowspan=3|(7-)
| rowspan=3|
| rowspan=3|
|-
| β<sup>+</sup>, α (2×10<sup>−5</sup>%)
| <sup>116</sup>Te
|-
| β<sup>+</sup>, p (7×10<sup>−6</sup>%)
| <sup>118</sup>I
|-
| <sup>121</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 66
| 120.917229(15)
| 155(4) s
| β<sup>+</sup>
| <sup>121</sup>Xe
| 3/2(+)
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>121m</sup>Cs
| rowspan=2 colspan="3" style="text-indent:2em" | 68.5(3) keV
| rowspan=2|122(3) s
| β<sup>+</sup> (83%)
| <sup>121</sup>Xe
| rowspan=2|9/2(+)
| rowspan=2|
| rowspan=2|
|-
| [[이성질핵 전이|IT]] (17%)
| <sup>121</sup>Cs
|-
| rowspan=2|<sup>122</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 67
| rowspan=2|121.91611(3)
| rowspan=2|21.18(19) s
| β<sup>+</sup>
| <sup>122</sup>Xe
| rowspan=2|1+
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, α (2×10<sup>−7</sup>%)
| <sup>118</sup>Te
|-
| style="text-indent:1em" | <sup>122m1</sup>Cs
| colspan="3" style="text-indent:2em" | 45.8 keV
| >1 µs
|
|
| (3)+
|
|
|-
| style="text-indent:1em" | <sup>122m2</sup>Cs
| colspan="3" style="text-indent:2em" | 140(30) keV
| 3.70(11) min
| β<sup>+</sup>
| <sup>122</sup>Xe
| 8-
|
|
|-
| style="text-indent:1em" | <sup>122m3</sup>Cs
| colspan="3" style="text-indent:2em" | 127.0(5) keV
| 360(20) ms
|
|
| (5)-
|
|
|-
| <sup>123</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 68
| 122.912996(13)
| 5.88(3) min
| β<sup>+</sup>
| <sup>123</sup>Xe
| 1/2+
|
|
|-
| style="text-indent:1em" | <sup>123m1</sup>Cs
| colspan="3" style="text-indent:2em" | 156.27(5) keV
| 1.64(12) s
| IT
| <sup>123</sup>Cs
| (11/2)-
|
|
|-
| style="text-indent:1em" | <sup>123m2</sup>Cs
| colspan="3" style="text-indent:2em" | 231.63+X keV
| 114(5) ns
|
|
| (9/2+)
|
|
|-
| <sup>124</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 69
| 123.912258(9)
| 30.9(4) s
| β<sup>+</sup>
| '''<sup>124</sup>Xe'''
| 1+
|
|
|-
| style="text-indent:1em" | <sup>124m</sup>Cs
| colspan="3" style="text-indent:2em" | 462.55(17) keV
| 6.3(2) s
| IT
| <sup>124</sup>Cs
| (7)+
|
|
|-
| <sup>125</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 70
| 124.909728(8)
| 46.7(1) min
| β<sup>+</sup>
| <sup>125</sup>Xe
| 1/2(+)
|
|
|-
| style="text-indent:1em" | <sup>125m</sup>Cs
| colspan="3" style="text-indent:2em" | 266.6(11) keV
| 900(30) ms
|
|
| (11/2-)
|
|
|-
| <sup>126</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 71
| 125.909452(13)
| 1.64(2) min
| β<sup>+</sup>
| '''<sup>126</sup>Xe'''
| 1+
|
|
|-
| style="text-indent:1em" | <sup>126m1</sup>Cs
| colspan="3" style="text-indent:2em" | 273.0(7) keV
| >1 µs
|
|
|
|
|
|-
| style="text-indent:1em" | <sup>126m2</sup>Cs
| colspan="3" style="text-indent:2em" | 596.1(11) keV
| 171(14) µs
|
|
|
|
|
|-
| <sup>127</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 72
| 126.907418(6)
| 6.25(10) h
| β<sup>+</sup>
| <sup>127</sup>Xe
| 1/2+
|
|
|-
| style="text-indent:1em" | <sup>127m</sup>Cs
| colspan="3" style="text-indent:2em" | 452.23(21) keV
| 55(3) µs
|
|
| (11/2)-
|
|
|-
| <sup>128</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 73
| 127.907749(6)
| 3.640(14) min
| β<sup>+</sup>
| '''<sup>128</sup>Xe'''
| 1+
|
|
|-
| <sup>129</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 74
| 128.906064(5)
| 32.06(6) h
| β<sup>+</sup>
| '''<sup>129</sup>Xe'''
| 1/2+
|
|
|-
| rowspan=2|<sup>130</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 75
| rowspan=2|129.906709(9)
| rowspan=2|29.21(4) min
| β<sup>+</sup> (98.4%)
| '''<sup>130</sup>Xe'''
| rowspan=2|1+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup> (1.6%)
| '''''<sup>130</sup>Ba'''''
|-
| rowspan=2 style="text-indent:1em" | <sup>130m</sup>Cs
| rowspan=2 colspan="3" style="text-indent:2em" | 163.25(11) keV
| rowspan=2|3.46(6) min
| IT (99.83%)
| <sup>130</sup>Cs
| rowspan=2|5-
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup> (0.16%)
| '''<sup>130</sup>Xe'''
|-
| <sup>131</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 76
| 130.905464(5)
| 9.689(16) d
| [[전자 포획|ε]]
| '''<sup>131</sup>Xe'''
| 5/2+
|
|
|-
| rowspan=2|<sup>132</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 77
| rowspan=2|131.9064343(20)
| rowspan=2|6.480(6) d
| β<sup>+</sup> (98.13%)
| '''<sup>132</sup>Xe'''
| rowspan=2|2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup> (1.87%)
| '''<sup>132</sup>Ba'''
|-
| <sup>133</sup>Cs<ref group="n">이 핵종의 원자핵이 [[절대 영도]]에서 [[바닥 상태]]에 있는 두 개의 초미세 에너지 준위의 주파수 차이를 9,192,631,770[[헤르츠|Hz]]로 정의하며, 그 역수가 [[SI 단위계]]에서의 1[[초 (시간)|초]]이다.</ref><ref group="n" name="FP">[[핵분열 생성물]]</ref>
| style="text-align:right" | 55
| style="text-align:right" | 78
| 132.905451933(24)
| colspan=3 align=center|'''안정'''<ref group="n">[[자발 핵분열]]이 가능할 것으로 추정된다.</ref>
| 7/2+
| 1.0000
|
|-
| rowspan=2|<sup>134</sup>Cs<ref group="n" name="FP" />
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 79
| rowspan=2|133.906718475(28)
| rowspan=2|2.0652(4) a
| β<sup>-</sup>
| '''<sup>134</sup>Ba'''
| rowspan=2|4+
| rowspan=2|
| rowspan=2|
|-
| ε (3×10<sup>−4</sup>%)
| '''<sup>134</sup>Xe'''
|-
| style="text-indent:1em" | <sup>134m</sup>Cs
| colspan="3" style="text-indent:2em" | 138.7441(26) keV
| 2.912(2) h
| IT
| <sup>134</sup>Cs
| 8-
|
|
|-
| <sup>135</sup>Cs<ref group="n" name="FP" />
| style="text-align:right" | 55
| style="text-align:right" | 80
| 134.9059770(11)
| 2.3 x10<sup>6</sup> a
| β<sup>-</sup>
| '''<sup>135</sup>Ba'''
| 7/2+
|
|
|-
| style="text-indent:1em" | <sup>135m</sup>Cs
| colspan="3" style="text-indent:2em" | 1632.9(15) keV
| 53(2) min
| IT
| <sup>135</sup>Cs
| 19/2-
|
|
|-
| <sup>136</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 81
| 135.9073116(20)
| 13.16(3) d
| β<sup>-</sup>
| '''<sup>136</sup>Ba'''
| 5+
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>136m</sup>Cs
| rowspan=2 colspan="3" style="text-indent:2em" | 518(5) keV
| rowspan=2|19(2) s
| β<sup>-</sup>
| '''<sup>136</sup>Ba'''
| rowspan=2|8-
| rowspan=2|
| rowspan=2|
|-
| IT
| <sup>136</sup>Cs
|-
| rowspan=2|[[세슘-137|<sup>137</sup>Cs]]<ref group="n" name="FP" />
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 82
| rowspan=2|136.9070895(5)
| rowspan=2|30.1671(13) a
| β<sup>-</sup> (95%)
| <sup>137m</sup>Ba
| rowspan=2|7/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup> (5%)
| '''<sup>137</sup>Ba'''
|-
| <sup>138</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 83
| 137.911017(10)
| 33.41(18) min
| β<sup>-</sup>
| '''<sup>138</sup>Ba'''
| 3-
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>138m</sup>Cs
| rowspan=2 colspan="3" style="text-indent:2em" | 79.9(3) keV
| rowspan=2|2.91(8) min
| IT (81%)
| <sup>138</sup>Cs
| rowspan=2|6-
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup> (19%)
| '''<sup>138</sup>Ba'''
|-
| <sup>139</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 84
| 138.913364(3)
| 9.27(5) min
| β<sup>-</sup>
| <sup>139</sup>Ba
| 7/2+
|
|
|-
| <sup>140</sup>Cs
| style="text-align:right" | 55
| style="text-align:right" | 85
| 139.917282(9)
| 63.7(3) s
| β<sup>-</sup>
| <sup>140</sup>Ba
| 1-
|
|
|-
| rowspan=2|<sup>141</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 86
| rowspan=2|140.920046(11)
| rowspan=2|24.84(16) s
| β<sup>-</sup> (99.96%)
| <sup>141</sup>Ba
| rowspan=2|7/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, [[중성자 방출|n]] (0.0349%)
| <sup>140</sup>Ba
|-
| rowspan=2|<sup>142</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 87
| rowspan=2|141.924299(11)
| rowspan=2|1.689(11) s
| β<sup>-</sup> (99.9%)
| <sup>142</sup>Ba
| rowspan=2|0-
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (0.091%)
| <sup>141</sup>Ba
|-
| rowspan=2|<sup>143</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 88
| rowspan=2|142.927352(25)
| rowspan=2|1.791(7) s
| β<sup>-</sup> (98.38%)
| <sup>143</sup>Ba
| rowspan=2|3/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (1.62%)
| <sup>142</sup>Ba
|-
| rowspan=2|<sup>144</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 89
| rowspan=2|143.932077(28)
| rowspan=2|994(4) ms
| β<sup>-</sup> (96.8%)
| <sup>144</sup>Ba
| rowspan=2|1(-#)
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (3.2%)
| <sup>143</sup>Ba
|-
| rowspan=2 style="text-indent:1em" | <sup>144m</sup>Cs
| rowspan=2 colspan="3" style="text-indent:2em" | 300(200)# keV
| rowspan=2|<1 s
| β<sup>-</sup>
| <sup>144</sup>Ba
| rowspan=2|(>3)
| rowspan=2|
| rowspan=2|
|-
| IT
| <sup>144</sup>Cs
|-
| rowspan=2|<sup>145</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 90
| rowspan=2|144.935526(12)
| rowspan=2|582(6) ms
| β<sup>-</sup> (85.7%)
| <sup>145</sup>Ba
| rowspan=2|3/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (14.3%)
| <sup>144</sup>Ba
|-
| rowspan=2|<sup>146</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 91
| rowspan=2|145.94029(8)
| rowspan=2|0.321(2) s
| β<sup>-</sup> (85.8%)
| <sup>146</sup>Ba
| rowspan=2|1-
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (14.2%)
| <sup>145</sup>Ba
|-
| rowspan=2|<sup>147</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 92
| rowspan=2|146.94416(6)
| rowspan=2|0.235(3) s
| β<sup>-</sup> (71.5%)
| <sup>147</sup>Ba
| rowspan=2|(3/2+)
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (28.49%)
| <sup>147</sup>Ba
|-
| rowspan=2|<sup>148</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 93
| rowspan=2|147.94922(62)
| rowspan=2|146(6) ms
| β<sup>-</sup> (74.9%)
| <sup>148</sup>Ba
| rowspan=2|
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n (25.1%)
| <sup>147</sup>Ba
|-
| rowspan=2|<sup>149</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 94
| rowspan=2|148.95293(21)#
| rowspan=2|150# ms [>50 ms]
| β<sup>-</sup>
| <sup>149</sup>Ba
| rowspan=2|3/2+#
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n
| <sup>148</sup>Ba
|-
| rowspan=2|<sup>150</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 95
| rowspan=2|149.95817(32)#
| rowspan=2|100# ms [>50 ms]
| β<sup>-</sup>
| <sup>150</sup>Ba
| rowspan=2|
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n
| <sup>149</sup>Ba
|-
| rowspan=2|<sup>151</sup>Cs
| rowspan=2 style="text-align:right" | 55
| rowspan=2 style="text-align:right" | 96
| rowspan=2|150.96219(54)#
| rowspan=2|60# ms [>50 ms]
| β<sup>-</sup>
| <sup>151</sup>Ba
| rowspan=2|3/2+#
| rowspan=2|
| rowspan=2|
|-
| β<sup>-</sup>, n
| <sup>150</sup>Ba
|}

== 각주 ==
<references/>
; 내용주
<references group="n" />

{{동위 원소 색인}}

{{전거 통제}}

[[분류:세슘|동위 원소]]
[[분류:세슘 동위 원소| ]]
[[분류:원소별 동위 원소 목록]]